--- /dev/null
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
--- /dev/null
+
+
+
+ALTER TABLE
+
+SQL - Language Statements
+
+
+
+ALTER TABLE
+
+
+Modifies table properties
+
+
+
+1998-04-15
+
+
+ALTER TABLE table
+ [*] ADD [COLUMN] column type
+ALTER TABLE table
+ [*] RENAME [COLUMN] column TO newcolumn
+ALTER TABLE table
+ RENAME TO newtable
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+Inputs</div>
<div class="diff add">+
+
+
+
+ table
+
+
+ The name of an existing table to alter.
+
+
+
+
+
+
+ column
+
+
+ Name of a new or existing column.
+
+
+
+
+
+
+ type
+
+
+ Type of the new column.
+
+
+
+
+
+
+ newcolumn
+
+
+ New name for an existing column.
+
+
+
+
+
+
+ newtable
+
+
+ New name for an existing column.
+
+
+
+
+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+Outputs</div>
<div class="diff add">+
+
+
+
+status
+
+
+
+
+
+ALTER
+
+
+ Message returned from column or table renaming.
+
+
+
+
+
+
+NEW
+
+
+ Message returned from column addition.
+
+
+
+
+
+
+ERROR
+
+
+ Message returned if table or column is not available.
+
+
+
+
+
+
+
+
+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+Description</div>
<div class="diff add">+
+ ALTER TABLE changes the definition of an existing table.
+ The new columns and their types are specified in the same style
+ and with the the same restrictions as in CREATE TABLE.
+ The RENAME clause causes the name of a table or column
+ to change without changing any of the data contained in
+ the affected table. Thus, the table or column will
+ remain of the same type and size after this command is
+ executed.
+ You must own the table in order to change its schema.
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+Notes</div>
<div class="diff add">+
+The keyword COLUMN is noise and can be omitted.
+
+ALTER TABLE/RENAME is a PostgreSQL language extension.
+
+[*]
following a name of a table indicates that statement
+ should be run over that table and all tables below it in the
+ inheritance hierarchy.
+ Refer to PostgreSQL User's Guide for further
+ information on inheritance.
+
+ Refer to the CREATE TABLE reference for further description
+ of valid arguments.
+
+
+
+
+
+
</div>
<div class="diff add">+Usage</div>
<div class="diff add">+
+ To add a column of type VARCHAR to a table:
+ ALTER TABLE distributors ADD COLUMN address VARCHAR(30);
+
+
+ To rename an existing column:
+ ALTER TABLE distributors RENAME COLUMN address TO city;
+
+
+ To rename an existing table:
+ ALTER TABLE distributors RENAME TO suppliers;
+
+
+
+
+
+
</div>
<div class="diff add">+Compatibility</div>
<div class="diff add">+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+SQL92</div>
<div class="diff add">+
+ SQL92 specifies some additional capabilities for ALTER TABLE
+ statement which are not yet directly supported by
Postgres:
+
+
+
+
+
+ALTER TABLE table ALTER [COLUMN] column
+ SET DEFAULT default
+ALTER TABLE table ALTER [COLUMN] column
+ ADD [CONSTRAINT constraint] table-constraint
+
+
+
+ Puts the default value or constraint specified into the
+ definition of column in the table. See CREATE TABLE for the
+ syntax of the default and table-constraint clauses.
+ If a default clause already exists, it will be replaced by
+ the new definition. If any constraints on this column already
+ exist, they will be retained using a boolean AND with the new
+ constraint.
+
+Currently, to set new default constraints on an existing column
+ the table must be recreated and reloaded:
+
+CREATE TABLE temp AS SELECT * FROM distributors;
+DROP TABLE distributors;
+CREATE TABLE distributors (
+ did DECIMAL(3) DEFAULT 1,
+ name VARCHAR(40) NOT NULL,
+ city VARCHAR(30)
+);
+INSERT INTO distributors SELECT * FROM temp;
+DROP TABLE temp;
+
+
+
+
+
+
+
+
+ALTER TABLE table
+ DROP DEFAULT default
+ALTER TABLE table
+ DROP CONSTRAINT constraint { RESTRICT | CASCADE }
+
+
+
+ Removes the default value specified by default or the rule
+ specified by constraint from the definition of a table.
+ If RESTRICT is specified only a constraint with no dependent
+ constraints can be destroyed.
+ If CASCADE is specified, Any constraints that are dependent on
+ this constraint are also dropped.
+
+Currently, to remove a default value or constraints on an
+ existing column the table must be recreated and reloaded:
+
+CREATE TABLE temp AS SELECT * FROM distributors;
+DROP TABLE distributors;
+CREATE TABLE distributors AS SELECT * FROM temp;
+DROP TABLE temp;
+
+
+
+
+
+ALTER TABLE table
+ DROP [COLUMN] column { RESTRICT | CASCADE }
+
+
+
+ Removes a column from a table.
+ If RESTRICT is specified only a column with no dependent
+ objects can be destroyed.
+ If CASCADE is specified, all objects that are dependent on
+ this column are also dropped.
+
+Currently, to remove an existing column the table must be
+ recreated and reloaded:
+
+CREATE TABLE temp AS SELECT did, city FROM distributors;
+DROP TABLE distributors;
+CREATE TABLE distributors (
+ did DECIMAL(3) DEFAULT 1,
+ name VARCHAR(40) NOT NULL,
+);
+INSERT INTO distributors SELECT * FROM temp;
+DROP TABLE temp;
+
+
+
+
+
+
--- /dev/null
+
+
+
+ ALTER USER
+
+ SQL - Language Statements
+
+
+
+ ALTER USER
+
+
+ Modifies user account information
+
+
+
+ 1998-04-15
+
+
+ ALTER USER username
+ [WITH PASSWORD password]
+ [CREATEDB | NOCREATEDB]
+ [CREATEUSER | NOCREATEUSER]
+ [IN GROUP groupname [, ...] ]
+ [VALID UNTIL 'abstime']
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+ Refer to CREATE USER statement for a detailed description of each
+ clause.
+
+
+
+
+ username
+
+
+ The Postgres account name of the user whose details are to be altered.
+
+
+
+
+
+ password
+
+
+ The new password to be used for this account.
+
+
+
+
+
+ groupname
+
+
+ The name of an access group into which this account is to be put.
+
+
+
+
+
+ abstime
+
+
+ The date (and, optionally, the time) at which this user's access is to be terminated.
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+ status
+
+
+
+
+
+ ALTER USER
+
+
+ Message returned if the alteration was successful.
+
+
+
+
+
+
+ ERROR: alterUser: user "username" does not exist
+
+
+ Error message returned if the user specified doesn't
+ exist.
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ ALTER USER is used to change the attributes of a user's
+ PostgreSQL account. Please note that it is not possible
+ to alter a user's "usesysid" via the alter user
+ statement. Also, it is only possible for the PostgreSQL
+ user or any user with read and modify permissions on
+ "pg_shadow" to alter user passwords.
+
+ If any of the clauses of the alter user statement are
+ omitted, the corresponding value in the "pg_shadow" table
+ is left unchanged.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ ALTER USER statement is a PostgreSQL language extension.
+
+ Refer to CREATE/DROP USER statements to create/remove an user
+ account.
+
+ At the current release (6.3.2), the IN GROUP clause is parsed
+ but has no effect. When it is fully implemented, it is
+ intended to modify the pg_group relation.
+
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ Change a user password
+
+ ALTER USER davide WITH PASSWORD hu8jmn3;
+
+ Change a user's valid until date
+
+ ALTER USER manuel VALID UNTIL 'Jan 31 2030';
+
+ Change a user's valid until date, specifying that his
+authorisation should expire at midday on 4th May 1998 using
+the time zone which is one hour ahead of UTC
+
+ ALTER USER chris VALID UNTIL 'May 4 12:00:00 1998 +1';
+
+ Give a user the ability to create other users and new databases.
+
+ ALTER USER miriam CREATEUSER CREATEDB;
+
+ Place a user in two groups
+
+ ALTER USER miriam IN GROUP sales, payroll;
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no ALTER USER statement in SQL92. The standard leaves
+ the definition of users to the implementation.
+
+
+
+
+
--- /dev/null
+
+
+
+ BEGIN WORK
+
+ SQL - Language Statements
+
+
+
+ BEGIN WORK
+
+
+ Begins a transaction
+
+
+
+
+
+ 1998-04-15
+
+
+ BEGIN { WORK | TRANSACTION }
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+ None
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+ status
+
+
+
+
+
+ BEGIN
+
+
+ This signifies that a new transaction has been started.
+
+
+
+
+
+
+ NOTICE: BeginTransactionBlock and not in default state
+
+
+
+ This indicates that a transaction was already in progress.
+
+ What happens to command queries already run
+ in the transaction? Does this have no effect, or does
+ it restart the transaction?
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ BEGIN begins a user transaction which PostgreSQL will
+ guarantee is serialisable with respect to all concurrently
+ executing transactions. PostgreSQL uses two-phase locking
+ to perform this task. If the transaction is committed,
+ PostgreSQL will ensure either that all updates are done orelse
+ that none of
+ them are done. Transactions have the standard ACID
+ (atomic, consistent, isolatable, and durable) property.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ The keyword TRANSACTION is just a cosmetic alternative to WORK.
+ Neither keyword need be specified.
+
+
+ BEGIN statement is a PostgreSQL language extension.
+
+
+ Refer to the LOCK statement for further information about locking
+ tables inside a transaction.
+
+
+ Use COMMIT or ROLLBACK to terminate a transaction.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+
To begin a user transaction:+
+ BEGIN WORK;
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no explicit "BEGIN WORK" in SQL92; transaction initiation
+ is always implicit and it terminates either with a COMMIT or with
+ a ROLLBACK statement.
+
+
+
+
+
+
--- /dev/null
+
+
+
+ CLOSE
+
+ SQL - Language Statements
+
+
+
+ CLOSE
+
+
+ Close a cursor
+
+
+
+
+ 1998-04-15
+
+
+CLOSE cursor
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+
+ cursor
+
+
+
+ The name of an open cursor to close.
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+
+ CLOSE
+
+
+
+ Message returned if the cursor is successfully closed.
+
+
+
+
+
+
+ NOTICE PerformPortalClose: portal "cursor" not found
+
+
+
+ This warning is given if
+ cursor is not
+ declared or has already been closed.
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ CLOSE frees the resources associated with an open cursor.
+ After the cursor is closed, no subsequent operations
+ are allowed on it. A cursor should be closed when it is
+ no longer needed.
+
+ An implicit close is executed for every open cursor when a
+ transaction is terminated by COMMIT or ROLLBACK.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ PostgreSQL does not have an explicit OPEN cursor statement;
+ a cursor is considered open when it is DECLAREd.
+ Use DECLARE to declare a cursor.
+
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ Close the cursor liahona:
+
+ CLOSE liahona;
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ CLOSE is fully compatibile with SQL92.
+
+
+
+
+
+
+
--- /dev/null
+
+
+
+ CLUSTER
+
+ SQL - Language Statements
+
+
+
+ CLUSTER
+
+
+ Gives storage clustering advice to PostgreSQL
+
+
+
+
+ 1998-04-15
+
+
+ CLUSTER indexname ON table
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+ indexname
+
+
+
+ The name of an index.
+
+
+
+
+
+
+ table
+
+
+
+ The name of a table.
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ CLUSTER
+
+
+ The clustering was done successfully.
+
+
+
+
+
+ ERROR: relation <tablerelation_number> inherits "invoice"
+
+
+ ???
+
+ This is not documented anywhere. It seems not to be possible to
+ cluster a table that is inherited.
+
+
+
+
+
+
+ ERROR: Relation x does not exist!
+
+
+ ???
+
+ The relation complained of was not shown in the error message,
+ which contained a random string instead of the relation name.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ This command instructs PostgreSQL to cluster the class specified
+ by classname approximately
+ based on the index specified by
+ indexname. The index must
+ already have been defined on classname.
+
+ When a class is clustered, it is physically reordered
+ based on the index information. The clustering is static.
+ In other words, as the class is updated, the changes are
+ not clustered. No attempt is made to keep new instances or
+ updated tuples clustered. If he wishes, the user can
+ recluster manually by issuing the command again.
+
+
+ The table is actually copied to a temporary table in index
+ order, then renamed back to the original name. For this
+ reason, all grant permissions and other indexes are lost
+ when clustering is performed.
+
+
+ In cases where you are accessing single rows randomly
+ within a table, the actual order of the data in the heap
+ table is unimportant. However, if you tend to access some
+ data more than others, and there is an index that groups
+ them together, you will benefit from using the CLUSTER
+ command.
+
+
+ Another place CLUSTER is good is in cases where you use an
+ index to pull out several rows from a table. If you are
+ requesting a range of indexed values from a table, or a
+ single indexed value that has multiple rows that match,
+ CLUSTER will help because once the index identifies the
+ heap page for the first row that matches, all other rows
+ that match are probably already on the same heap page,
+ saving disk accesses and speeding up the query.
+
+
+ There are two ways to cluster data. The first is with the
+ CLUSTER command, which reorders the original table with
+ the ordering of the index you specify. This can be slow
+ on large tables because the rows are fetched from the heap
+ in index order, and if the heap table is unordered, the
+ entries are on random pages, so there is one disk page
+ retrieved for every row moved. PostgreSQL has a cache,
+ but the majority of a big table will not fit in the cache.
+
+
+ Another way is to use
+
SELECT ... INTO TABLE temp FROM ... ORDER BY ...+ This uses the PostgreSQL sorting code in
+ ORDER BY to match the index, and is much faster for
+ unordered data. You then drop the old table, use
+ to rename 'temp' to the old name, and
+ recreate the b bindexes. The only problem is that oids
+ will not be preserved. From then on, CLUSTER should be
+ fast because most of the heap data has already been
+ ordered, and the existing index is used.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ Cluster the employees relation on the basis of its salary attribute
+
+ CLUSTER emp_ind ON emp
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no CLUSTER statement in SQL92.
+
+
+
+
+
+
+
--- /dev/null
+
+
Commands
+
+
+
+&alterTable;
+&alterUser;
+&begin;
+&close;
+&cluster;
+&commit;
+©
+&createAggregate;
+&createDatabase;
+&createFunction;
+&createIndex;
+&createLanguage;
+&dropFunction;
+&select;
+
+
+
+
\ No newline at end of file
--- /dev/null
+
+
+
+ COMMIT
+
+ SQL - Language Statements
+
+
+
+ COMMIT
+
+
+ Commits the current transaction
+
+
+
+
+
+ 1998-04-15
+
+
+ COMMIT [ WORK ]
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ None
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ END
+
+
+Message returned if the transaction is successfully committed.
+
+
+
+
+
+ NOTICE EndTransactionBlock and not inprogress/abort state
+
+
+
+If there is no transaction in progress.
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ COMMIT commits the current transaction. All
+ changes made by the transaction become visible to others
+ and are guaranteed to be durable if a crash occurs.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ The keyword WORK is noise and can be omitted.
+
+ Refer to ROLLBACK statements to abort a transaction.
+
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+To make all changes permanent:
+
+ COMMIT WORK;
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ Full compatibility.
+
+
+
+
+
+
+
--- /dev/null
+
+
+
+ COPY
+
+ SQL - Language Statements
+
+
+
+ COPY
+
+
+ Copies data between files and tables
+
+
+
+ 1998-04-15
+
+
+ COPY [BINARY] table [WITH OIDS]
+ TO|FROM 'filename'|stdin|stdout
+ [USING DELIMITERS 'delimiter']
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ table
+
+
+ The name of a table.
+
+
+
+
+
+ delimiter
+
+
+ A character that delimits fields.
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+ Status
+
+
+
+
+
+ COPY
+
+
+ The copy completed successfully.
+
+
+
+
+
+ ERROR: error message
+
+
+ The copy failed for the reason stated in the error message.
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ COPY moves data between PostgreSQL tables and
+ standard Unix files. The keyword BINARY
+ changes the behavior of field formatting, as described
+ below. Table is the
+ name of an existing table. The keyword WITH
+ OIDS copies the internal unique object id (OID) for each
+ row. Filename is the
+ absolute Unix pathname of the file. In place of a filename, the
+ keywords stdin and stdout
+ can be used, so that input to COPY can be written
+ by a libpq application and output from COPY can
+ be read by a libpq application.
+
+ The BINARY keyword will force all data to be
+ stored/read as binary objects rather than as ASCII text. It is
+ somewhat faster than the normal copy command, but is not
+ generally portable, and the files generated are somewhat larger,
+ although this factor is highly dependent on the data itself. By
+ default, an ASCII copy uses a tab (\t) character as a delimiter.
+ The delimiter may also be changed to any other single character
+ with the keyword USING DELIMITERS. Characters
+ in data fields which happen to match the delimiter character will
+ be quoted.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ You must have select access on any table whose values are read by
+ COPY, and either insert or update access to a
+ table into which values are being inserted by COPY.
+ The backend also needs appropriate Unix permissions for any file read
+ or written by COPY.
+
+Is this right? The man page talked of read, write and append access, which
+is neither SQL nor Unix terminology.
+
+
+ The keyword USING DELIMITERS is inaptly
+ named, since only a single character may be specified. (If a
+ group of characters is specified, only the first character is
+ used.)
+
+ WARNING: do not confuse COPY with the
+ psql instruction \copy.
+
+
+
+
+
+ 1998-05-04
+
+
Format of output files
+
+
+ 1998-05-04
+
+
ASCII copy format
+ When COPY is used without BINARY,
+ the file generated will have each instance on a single line, with each
+ attribute separated by the delimiter character. Embedded
+ delimiter characters will be preceded by a backslash character
+ (\). The attribute values themselves are strings generated by the
+ output function associated with each attribute type. The output
+ function for a type should not try to generate the backslash
+ character; this will be handled by COPY itself.
+
+ The actual format for each instance is
+ <attr1><separator><attr2><separator>...<separator><attrn><newline>
+ The oid is placed on the beginning of the line
+ if WITH OIDS is specified.
+
+ If COPY is sending its output to standard
+ output instead of a file, it will send a backslash(\) and a period
+ (.) followed immediately by a newline, on a separate line,
+ when it is done. Similarly, if COPY is reading
+ from standard input, it will expect a backslash (\) and a period
+ (.) followed by a newline, as the first three characters on a
+ line, to denote end-of-file. However, COPY
+ will terminate (followed by the backend itself) if a true EOF is
+ encountered.
+
+ The backslash character has special meaning. NULL attributes are
+ output as \N. A literal backslash character is output as two
+ consecutive backslashes. A literal tab character is represented
+ as a backslash and a tab. A literal newline character is
+ represented as a backslash and a newline. When loading ASCII data
+ not generated by PostgreSQL, you will need to convert backslash
+ characters (\) to double-backslashes (\\) to ensure that they are loaded
+ properly.
+
+
+
+
+ 1998-05-04
+
+
Binary copy format
+ In the case of COPY BINARY, the first four
+ bytes in the file will be the number of instances in the file. If
+ this number is zero, the COPY BINARY command
+ will read until end of file is encountered. Otherwise, it will
+ stop reading when this number of instances has been read.
+ Remaining data in the file will be ignored.
+
+ The format for each instance in the file is as follows. Note that
+ this format must be followed exactly.
+ Unsigned four-byte integer quantities are called uint32 in the
+ table below.
+
+
Contents of a binary copy file
+
+
+
+
+
+ |
+ At the start of the file
+
+ |
+ uint32
+ number of tuples
+
+ |
+ For each tuple
+
+ |
+ uint32
+ total length of tuple data
+
+ |
+ uint32
+ oid (if specified)
+
+ |
+ uint32
+ number of null attributes
+
+ |
+ [uint32
+ attribute number of first null attribute, counting from 0
+
+ |
+ ...
+ ...
+
+ |
+ uint32
+ attribute number of last null attribute]
+
+ |
+ -
+ <tuple data>
+
+
+
+
+
+
+
+
+ 1998-05-04
+
+
Alignment of binary data
+ On Sun-3s, 2-byte attributes are aligned on two-byte boundaries,
+ and all larger attributes are aligned on four-byte boundaries.
+ Character attributes are aligned on single-byte boundaries. On
+ other machines, all attributes larger than 1 byte are aligned on
+ four-byte boundaries. Note that variable length attributes are
+ preceded by the attribute's length; arrays are simply contiguous
+ streams of the array element type.
+
+
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+To copy a table to standard output, using | as a delimiter
+
+ COPY country TO stdout USING DELIMITERS '|';
+
+ To copy data from a Unix file into a table:
+
+ COPY country FROM '/usr1/proj/bray/sql/country_data';
+
+ A sample of data suitable for copying into a table from stdin (so it
+has the termination sequence on the last line):
+
+ AF AFGHANISTAN
+ AL ALBANIA
+ DZ ALGERIA
+ ...
+ ZM ZAMBIA
+ ZW ZIMBABWE
+ \.
+
+ The same data, output in binary format on a Linux Intel machine.
+ The data is shown after filtering through the Unix utility od -c. The table has
+ three fields; the first is char(2) and the second is text. All the
+ rows have a null value in the third field). Notice how the char(2)
+ field is padded with nulls to four bytes and the text field is
+ preceded by its length:
+
+ 355 \0 \0 \0 027 \0 \0 \0 001 \0 \0 \0 002 \0 \0 \0
+ 006 \0 \0 \0 A F \0 \0 017 \0 \0 \0 A F G H
+ A N I S T A N 023 \0 \0 \0 001 \0 \0 \0 002
+ \0 \0 \0 006 \0 \0 \0 A L \0 \0 \v \0 \0 \0 A
+ L B A N I A 023 \0 \0 \0 001 \0 \0 \0 002 \0
+ \0 \0 006 \0 \0 \0 D Z \0 \0 \v \0 \0 \0 A L
+ G E R I A
+ ... \n \0 \0 \0 Z A M B I A 024 \0
+ \0 \0 001 \0 \0 \0 002 \0 \0 \0 006 \0 \0 \0 Z W
+ \0 \0 \f \0 \0 \0 Z I M B A B W E
+
+
+
+
+
See also
+ insert(l), create table(l), vacuum(l), libpq.
+
+
+
+
+
Bugs
+ COPY stops operation at the first error. This
+ should not lead to problems in the event of a copy from, but the
+ target relation will, of course, be partially modified in a copy
+ to. The VACUUM query should be used to clean up
+ after a failed copy.
+
+ Because Postgres' current directory is not the same as the user's
+ working directory, the result of copying to a file "foo" (without
+ additional path information) may yield unexpected results for the
+ naive user. In this case, "foo" will wind up in $PGDATA/foo. In
+ general, the full pathname should be used when specifying files to
+ be copied.
+
+ Files used as arguments to the copy command must reside on or be
+ accessible to the database server machine by being either on
+ local disks or on a networked file system.
+
+ When a TCP/IP connection from one machine to another is used, and a
+ target file is specified, the target file will be written on the
+ machine where the backend is running rather than the user's
+ machine.
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no COPY statement in SQL92.
+
+
+
+
+
+
--- /dev/null
+
+
+
+ CREATE AGGREGATE
+
+ SQL - Language Statements
+
+
+This entry needs a lot of work, especially some
+usefully complex examples. Since I don't yet understand it, I
+haven't done this.
+
+
+
+ CREATE AGGREGATE
+
+
+ Defines a new aggregate function
+
+
+
+ 1998-04-15
+
+
+ CREATE AGGREGATE name [AS]
+ ([ SFUNC1 = state_transition_function1
+ , BASETYPE = data_type
+ , STYPE1 = sfunc1_return_type ]
+ [, SFUNC2 = state_transition_function2
+ , STYPE2 = sfunc2_return_type ]
+ [, FINALFUNC = final_function ]
+ [, INITCOND1 = initial_condition1 ]
+ [, INITCOND2 = initial_condition2 ]
+ )
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+ name
+
+
+ The name of an aggregate function to create.
+
+
+
+
+
+ state_transition_function1
+
+
+
+
+
+
+
+ data_type
+
+
+
+
+
+
+
+ sfunc1_return_type
+
+
+
+
+
+
+
+ state-transition_function2
+
+
+
+
+
+
+
+ sfunc2_return_type
+
+
+
+
+
+
+
+ final_function
+
+
+
+
+
+
+
+ initial_condition1
+
+
+
+
+
+
+
+ initial_condition2
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ CREATE
+
+
+ Message returned if the command completes successfully.
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ An aggregate function can use up to three functions, two
+ state transition functions, X1 and X2:
+ X1( internal-state1, next-data_item ) ---> next-internal-state1
+ X2( internal-state2 ) ---> next-internal-state2
+ and a final calculation function, F:
+ F(internal-state1, internal-state2) ---> aggregate-value
+ These functions are required to have the following properties:
+
+
+ The arguments to state-transition-function-1 must
+ be (stype1,basetype), and its return value must be
+ stype1.
+
+
+
+ The argument and return value of state-transition-
+ function-2 must be stype2.
+
+
+
+ The arguments to the final-calculation-function
+ must be (stype1,stype2), and its return value must
+ be a POSTGRES base type (not necessarily the same
+ as basetype.
+
+
+
+ The final-calculation-function should be specified
+ if and only if both state-transition functions are
+ specified.
+
+
+
+
+ Note that it is possible to specify aggregate functions
+ that have varying combinations of state and final functions.
+ For example, the "count" aggregate requires sfunc2
+ (an incrementing function) but not sfunc1 or finalfunc,
+ whereas the "sum" aggregate requires sfunc1 (an addition
+ function) but not sfunc2 or finalfunc and the "average"
+ aggregate requires both of the above state functions as
+ well as a finalfunc (a division function) to produce its
+ answer. In any case, at least one state function must be
+ defined, and any sfunc2 must have a corresponding initcond2.
+
+ Aggregates also require two initial conditions, one for
+ each transition function. These are specified and stored
+ in the database as fields of type text.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ CREATE AGGREGATE function is a PostgreSQL language extension.
+
+
+ Refer to DROP AGGREGATE function to drop aggregate functions.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no CREATE AGGREGATE function on SQL92.
+
+
+
+
+
--- /dev/null
+
+
+
+ CREATE DATABASE
+
+ SQL - Language Statements
+
+
+
+ CREATE DATABASE
+
+
+ Creates a new database
+
+
+
+ 1998-04-15
+
+
+ CREATE DATABASE name [WITH LOCATION = 'dbpath']
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ name
+
+
+ The name of a database to create.
+
+
+
+
+
+ dbpath
+
+
+ An alternate location can be specified as either an
+ environment variable known to the backend server
+ (e.g. 'PGDATA2') or as an absolute path name
+ (e.g. '/usr/local/pgsql/data').
+ In either case, the location must be pre-configured
+ by initlocation.
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ CREATEDB
+
+
+ Message returned if the command completes successfully.
+
+
+
+
+
+ WARN: createdb: database "name" already exists.
+
+
+ This occurs if database specified already exists.
+
+
+
+
+
+ ERROR: Unable to create database directory directory
+
+
+
+There was a problem with creating the required directory; this operation will
+ need permissions for the postgres user on the specified location.
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ CREATE DATABASE creates a new PostgreSQL database.
+ The creator becomes the administrator of the new database.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ CREATE DATABASE statement is a PostgreSQL language extension.
+
+ Refer to DROP DATABASE statement to remove a database.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ To create a new database:
+
+ CREATE DATABASE lusiadas;
+
+ To create a new database in ~/private_db:
+
+ $ mkdir private_db
+ $ initlocation ~/private_db
+ Creating Postgres database system directory /home/olly/private_db/base
+
+ $ chmod a+rx private_db
+ $ chmod a+rwx private_db/base
+ $ psql
+ Welcome to the POSTGRESQL interactive sql monitor:
+ Please read the file COPYRIGHT for copyright terms of POSTGRESQL
+
+ type \? for help on slash commands
+ type \q to quit
+ type \g or terminate with semicolon to execute query
+ You are currently connected to the database: template1
+
+ template1=> create database elsewhere with location = '/home/olly/private_db';
+ CREATEDB
+
+
+
+
+
</div>
<div class="diff add">+ Bugs</div>
<div class="diff add">+
+ Where an ordinary user cannot change the ownership of files to other users
+ (which is correct from a security point of view), there is no easy way
+ to give the postgres backend access to files in a database at a
+ non-standard location without
+ giving similar access to all users. The situation shown in the usage
+ example makes /home/olly/private_db world-accessible.
+
+ If, on the other hand, the user gets the system administrator to give
+ file ownership to the postgres superuser and restrict access, he will
+ then be unable to delete the directory/base directory.
+
+
+ initlocation does not create a PG_VERSION file in the specified location.
+ How will PostgreSQL handle the situation if it is upgraded to an
+ incompatible database version?
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no CREATE DATABASE statement on SQL92.
+
+ The equivalent command in standard SQL is CREATE SCHEMA.
+
+
+
+
+
+
+
--- /dev/null
+
+
+
+ CREATE FUNCTION
+
+ SQL - Language Statements
+
+
+
+ CREATE FUNCTION
+
+
+ Defines a new function
+
+
+
+
+ 1998-04-15
+
+
+ CREATE FUNCTION name ([ftype [, ...]])
+ RETURNS rtype
+ AS path
+ LANGUAGE 'langname'
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ name
+
+
+ The name of a function to create.
+
+
+
+
+
+ ftype
+
+
+ The data type of function arguments.
+
+
+
+
+
+ rtype
+
+
+ The return data type.
+
+
+
+
+
+ path
+
+
+ May be either an SQL-query or an absolute path to an
+ object file.
+
+
+
+
+
+ langname
+
+
+ may be 'c', 'sql', 'internal' or 'plname'.
+ (where 'plname' is the language name of a created procedural
+ language. See CREATE LANGUAGE for details).
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ CREATE
+
+
+ This is returned if the command completes successfully.
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ With this command, a PostgreSQL user can register a function
+ with PostgreSQL. Subsequently, this user is treated as the
+ owner of the function.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ Refer to PostgreSQL User's Guide chapter 6 for further information.
+ This reference needs to be corrected.
+
+ Refer to the
+ DROP FUNCTION
+ statement to drop functions.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ To create a simple SQL function:
+
+ CREATE FUNCTION one() RETURNS int4
+ AS 'SELECT 1 AS RESULT'
+ LANGUAGE 'sql';
+
+ SELECT one() AS answer;
+
+ answer
+ ------
+ 1
+
+ To create a C function, calling a routine from a user-created
+ shared library. This particular routine calculates a check
+ digit and returns TRUE if the check digit in the function parameters
+ is correct. It is intended for use in a CHECK contraint.
+
+ CREATE FUNCTION ean_checkdigit(bpchar, bpchar) RETURNS bool
+ AS '/usr1/proj/bray/sql/funcs.so' LANGUAGE 'c';
+
+ CREATE TABLE product
+ (
+ id char(8) PRIMARY KEY,
+ eanprefix char(8) CHECK (eanprefix ~ '[0-9]{2}-[0-9]{5}')
+ REFERENCES brandname(ean_prefix),
+ eancode char(6) CHECK (eancode ~ '[0-9]{6}'),
+ CONSTRAINT ean CHECK (ean_checkdigit(eanprefix, eancode))
+ );
+
+
+
+
+
</div>
<div class="diff add">+ Bugs</div>
<div class="diff add">+
+ A C function cannot return a set of values.
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+ The CREATE FUNCTION statement is a PostgreSQL language extension.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL/PSM<footnote></div>
<div class="diff add">+ <para></div>
<div class="diff add">+ PSM stands for Persistent Stored Modules, it is a procedural</div>
<div class="diff add">+ language and it was originally hoped that PSM would be ratified</div>
<div class="diff add">+ as an official standard by late 1996. However PSM will</div>
<div class="diff add">+ eventually become a standard.</div>
<div class="diff add">+ </para></div>
<div class="diff add">+ </footnote></div>
<div class="diff add">+
+ The SQL/PSM CREATE FUNCTION statement has the following syntax:
+ CREATE FUNCTION name
+ ( [ [IN|OUT|INOUT] parm type [, ...] ])
+ RETURNS rtype
+ LANGUAGE 'langname'
+ ESPECIFIC routine
+ SQL-statement
+
+
+
+
+
+
+
+
--- /dev/null
+
+
+
+ CREATE INDEX
+
+ SQL - Language Statements
+
+
+
+ CREATE INDEX
+
+
+ Constructs a secondary index
+
+
+
+ 1998-04-15
+
+
+ CREATE [UNIQUE] INDEX index_name
+ ON table [USING acc_name ]
+ ( column [ops_name] [, ...] )
+
+ CREATE [UNIQUE] INDEX index_name
+ ON table [USING acc_name ]
+ ( func_name( column [, ... ]) ops_name )
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ UNIQUE
+
+
+ UNIQUE causes the system to check for
+ duplicate values when the index is created (if data
+ already exist) and each time data is added. Attempts to
+ insert or update non-duplicate data will generate an
+ error.
+
+
+
+
+
+ index_name
+
+
+ The name of the index to be created.
+
+
+
+
+
+ table
+
+
+ The name of the table to be indexed.
+
+
+
+
+
+ acc_name
+
+
+ the name of the access method which is to be used for
+ the index. The default access method is BTREE.
+ Postgres provides three access methods for secondary indices:
+
+
+ BTREE
+
+ an implementation of the Lehman-Yao
+ high-concurrency btrees.
+
+
+
+
+ RTREE
+
+
implements standard rtrees using Guttman's+ quadratic split algorithm.
+
+
+
+
+ HASH
+
+ an implementation of Litwin's linear hashing.
+
+
+
+
+
+
+
+
+
+ column
+
+
+ The name of a column of the table.
+
+
+
+
+
+ ops_name
+
+
+ An associated operator class.
+ The following select list returns all ops_names:
+
+ SELECT am.amname AS acc_name,
+ opc.opcname AS ops_name,
+ opr.oprname AS ops_comp
+ FROM pg_am am, pg_amop amop,
+ pg_opclass opc, pg_operator opr
+ WHERE amop.amopid = am.oid AND
+ amop.amopclaid = opc.oid AND
+ amop.amopopr = opr.oid
+ ORDER BY acc_name, ops_name, ops_comp
+
+
+
+
+
+
+ func_name
+
+
+ A user-defined function, which returns a value that can
+ be indexed.
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ CREATE
+
+
+ The message returned if the index is successfully created.
+
+
+
+
+
+ ERROR: Cannot create index: 'index_name' already exists.
+
+
+ This error occurs if it is impossible to create the index.
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ This command constructs an index called index_name.
+
+ In the first syntax shown above, the key fields for the
+ index are specified as column names; a column may also have
+ an associated operator class. An operator class is used
+ to specify the operators to be used for a particular
+ index. For example, a btree index on four-byte integers
+ would use the int4_ops class;
+ this operator class includes
+ comparison functions for four-byte integers. The default
+ operator class is the appropriate operator class for that
+ field type.
+
+ In the second syntax, an index is defined
+ on the result of a user-defined function
+ func_name applied
+ to one or more attributes of a single class. These functional
+ indices can be used to obtain fast access to data
+ based on operators that would normally require some
+ transformation to apply them to the base data.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ Currently, only the BTREE access method supports multi-column
+ indices. Up to 7 keys may be specified.
+
+ Use the
+ DROP INDEX
+
+ statement to remove indexes.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+
To create a btree index on the field title+ in the table films:
+
+ CREATE UNIQUE INDEX title_idx
+ ON films (title);
+
+ To create a rtree index on a point attribute so that we
+ can efficiently use box operators on the result of the
+ conversion function:
+
+ CREATE INDEX pointloc
+ ON points USING RTREE (point2box(location) box_ops);
+
+ SELECT * FROM points
+ WHERE point2box(points.pointloc) = boxes.box;
+
+Is this example correct?
+
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ CREATE INDEX is a PostgreSQL language extension.
+
+ There is no CREATE INDEX command in SQL92.
+
+
+
+
+
+
+
--- /dev/null
+
+
+
+ CREATE LANGUAGE
+
+ SQL - Language Statements
+
+
+
+ CREATE LANGUAGE
+
+
+ Defines a new language for functions
+
+
+
+
+ 1998-04-15
+
+
+ CREATE [TRUSTED] PROCEDURAL LANGUAGE 'langname'
+ HANDLER call_handler
+ LANCOMPILER 'comment'
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ TRUSTED
+
+
+ TRUSTED specifies that the call handler for
+ the language is safe; that is, it offers an unprivileged user
+ no functionality to get around access restrictions. If
+ this keyword is omitted when registering the language,
+ only users with the PostgreSQL superuser privilege can use
+ this language to create new functions
+ (like the 'C' language).
+
+
+
+
+
+
+ langname
+
+
+ The name of the new procedural language.
+ The language name is case insensitive. A procedural
+ language cannot override one of the built-in languages of
+ PostgreSQL.
+
+
+
+
+
+ call_handler
+
+
+ The argument for HANDLER is the name
+ of a previously
+ registered function that will be called to execute the PL
+ procedures.
+
+
+
+
+
+ comment
+
+
+ The LANCOMPILER argument is the
+ string that will be
+ inserted in the LANCOMPILER attribute
+ of the new
+ pg_language entry. At present,
+ PostgreSQL doesn't use
+ this attribute in any way.
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ CREATE
+
+
+ This message is returned if the language is successfully
+ created.
+
+
+
+
+
+ ERROR: PL handler function funcname() doesn't exist
+
+
+ This error is returned if the function
+ funcname()
+ is not found.
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ Using CREATE LANGUAGE, a PostgreSQL user can register
+ a new language with PostgreSQL. Subsequently, functions and
+ trigger procedures can be defined in this new language.
+ The user must have the PostgreSQL superuser privilege to
+ register a new language.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Writing PL handlers</div>
<div class="diff add">+
+ The call handler for a procedural language must be written
+ in a compiler language such as 'C' and registered with
+ PostgreSQL as a function taking no arguments and returning
+ opaque type.
+ What does `opaque type' mean?
+ This prevents the call handler from being
+ called directly as a function from queries.
+
+ However, arguments must be supplied on the actual call when a
+ PL function or trigger
+ procedure in the language offered by the handler is to be
+ executed.
+
+
+ When called from the trigger manager, the only argument is
+ the object ID from the procedure's pg_proc
+ entry. All other
+ information from the trigger manager is found in the
+ global CurrentTriggerData pointer.
+
+
+
+ When called from the function manager, the arguments are
+ the object ID of the procedure's pg_proc
+ entry, the number
+ of arguments given to the PL function, the arguments in a
+ FmgrValues structure and a pointer
+ to a boolean where the
+ function tells the caller if the return value is the SQL
+ NULL value.
+
+
+
+
+ It's up to the call handler to fetch the
+ pg_proc entry and
+ to analyze the argument and return types of the called
+ procedure. The AS clause from the
+ CREATE FUNCTION of
+ the procedure will be found in the prosrc
+ attribute of the
+ pg_proc entry. This may be the
+ source text in the procedural
+ language itself (like for PL/Tcl), a pathname to a
+ file or anything else that tells the call handler what to
+ do in detail.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ Use
+ CREATE FUNCTION
+
+ to create a function.
+
+ Use
+ DROP LANGUAGE
+ to drop procedural languages.
+
+ Refer to the table pg_language
+ for further information:
+
+ Table = pg_language
+ +--------------------------+--------------------------+-------+
+ | Field | Type | Length|
+ +--------------------------+--------------------------+-------+
+ | lanname | name | 32 |
+ | lancompiler | text | var |
+ +--------------------------+--------------------------+-------+
+
+ lanname |lancompiler
+ --------+--------------
+ internal|n/a
+ lisp |/usr/ucb/liszt
+ C |/bin/cc
+ sql |postgres
+
+
+
+
+
+
+
+
</div>
<div class="diff add">+ Restrictions</div>
<div class="diff add">+
+ Since the call handler for a procedural language must be
+ registered with PostgreSQL in the 'C' language, it inherits
+ all the restrictions of 'C' functions.
+
+ What are these restrictions?
+
+
+
+
+
</div>
<div class="diff add">+ Bugs</div>
<div class="diff add">+
+ At present, the definitions for a procedural language cannot be
+ changed once they have been created.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ This is a template for a PL handler written in 'C':
+
+ #include "executor/spi.h"
+ #include "commands/trigger.h"
+ #include "utils/elog.h"
+ #include "fmgr.h" /* for FmgrValues struct */
+ #include "access/heapam.h"
+ #include "utils/syscache.h"
+ #include "catalog/pg_proc.h"
+ #include "catalog/pg_type.h"
+
+ Datum
+ plsample_call_handler(
+ Oid prooid,
+ int pronargs,
+ FmgrValues *proargs,
+ bool *isNull)
+ {
+ Datum retval;
+ TriggerData *trigdata;
+
+ if (CurrentTriggerData == NULL) {
+ /*
+ * Called as a function
+ */
+
+ retval = ...
+ } else {
+ /*
+ * Called as a trigger procedure
+ */
+ trigdata = CurrentTriggerData;
+ CurrentTriggerData = NULL;
+
+ retval = ...
+ }
+
+ *isNull = false;
+ return retval;
+ }
+
+ Only a few thousand lines of code have to be added instead
+ of the dots to complete the PL call handler. See
+ CREATE FUNCTION
+ for information on how to compile
+ it into a loadable module
+.
+ The following commands then register the sample procedural
+ language.
+ CREATE FUNCTION plsample_call_handler () RETURNS opaque
+ AS '/usr/local/pgsql/lib/plsample.so'
+ LANGUAGE 'C';
+
+ CREATE PROCEDURAL LANGUAGE 'plsample'
+ HANDLER plsample_call_handler
+ LANCOMPILER 'PL/Sample';
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+ CREATE LANGUAGE is a PostgreSQL extension.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no CREATE LANGUAGE statement in SQL92.
+
+
+
+
+
+
+
--- /dev/null
+
+
+
+ DROP FUNCTION
+
+ SQL - Language Statements
+
+
+
+ DROP FUNCTION
+
+
+ Removes a user-defined C function
+
+
+
+
+ 1998-04-15
+
+
+ DROP FUNCTION name ( [type [, ...]] )
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ name
+
+
+ The name of an existing function.
+
+
+
+
+
+ type
+
+
+ The type of function parameters.
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+
+
+
+
+
+ DROP
+
+
+ Message returned if the command completes successfully.
+
+
+
+
+
+
+ WARN RemoveFunction: Function "name" ("types") does not exist
+
+
+ This message is given if the function specified does not
+exist into database.
+
+
+
+
+
+
+
+
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ DROP FUNCTION will remove references to an existing C
+ function. To execute this command the user must be the
+ owner of the function. The input argument types to the
+ function must be specified, as only the function with the
+ given name and argument types will be removed.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ Refer to the
+
+ CREATE FUNCTION
+
+ statement to create aggregate functions.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ This command removes the square root function:
+
+ DROP FUNCTION sqrt(int4);
+
+
+
+
</div>
<div class="diff add">+ Bugs</div>
<div class="diff add">+
+ No checks are made to ensure that types, operators or access
+ methods that rely on the function have been removed first.
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+ >DROP FUNCTION statement is a PostgreSQL language extension.
+
+
+
+
+ 1998-04-15
+
+
</div>
<div class="diff add">+ SQL/PSM</div>
<div class="diff add">+
+ The SQL/PSM DROP FUNCTION statement has the following syntax:
+ DROP [ SPECIFIC ] FUNCTION name { RESTRICT | CASCADE }
+
+
+
+
+
+
--- /dev/null
+
+
+
+SELECT
+
+SQL - Language Statements
+
+
+
+SELECT
+
+
+Retrieve rows from a table or view
+
+
+
+1998-04-15
+
+
+
+
+SELECT [ALL|DISTINCT]
+ expression [AS name] [, ...]
+ [INTO [TABLE] intable]
+ [FROM table [alias] [, ...] ]
+ [WHERE condition]
+ [GROUP BY column [, ...] ]
+ [HAVING condition [, ...] ]
+ [UNION [ALL] select]
+ [ORDER BY column [ASC | DESC] [, ...] ]
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+Inputs</div>
<div class="diff add">+
+
+
+
+
+expression
+
+
+ The name of a table's column or an expression.
+
+
+
+
+
+
+name
+
+
+ Specifies another name for a column or an expression using
+ the AS clause. name cannot be used in the WHERE
+ condition. It can, however, be referenced in associated
+ ORDER BY or GROUP BY clauses.
+
+
+
+
+
+
+intable
+
+
+ If the INTO TABLE clause is specified, the result of the
+ query will be stored in another table with the indicated
+ name.
+If intable does not exist, it will be created automatically.
+
+
+The CREATE TABLE AS statement will also create a new table from a select query.
+
+
+
+
+
+
+
+
+table
+
+
+ The name of an existing table referenced by FROM clause.
+
+
+
+
+
+
+alias
+
+
+An alternate name for the preceeding table.
+Used for brevity or to eliminate ambiguity for joins within a single table.
+
+
+
+
+
+
+condition
+
+
+An expression leading to a boolean (true/false) result.
+See the WHERE clause.
+
+
+
+
+
+
+column
+
+
+ The name of a table's column.
+
+
+
+
+
+
+select
+
+
+A select statement with all features except the ORDER BY clause.
+
+
+
+
+
+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+Outputs</div>
<div class="diff add">+
+
+
+
+ Rows
+
+
+The complete set of rows resulting from the query specification.
+
+
+
+
+
+
+count
+
+
+The count of rows returned by the query.
+
+
+
+
+
+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+Description</div>
<div class="diff add">+
+ SELECT will get all rows which satisfy the WHERE condition
+ or all rows of a table if WHERE is omitted.
+
+ The GROUP BY clause allows a user to divide a table
+ conceptually into groups. (See GROUP BY clause).
+
+ The HAVING clause specifies a grouped table derived by the
+ elimination of groups from the result of the previously
+ specified clause. (See HAVING clause).
+
+ The ORDER BY clause allows a user to specify that he/she
+ wishes the rows sorted according to the ASCending or
+ DESCending mode operator. (See ORDER BY clause)
+
+ The UNION clause specifies a table derived from a Cartesian
+ product union join. (See UNION clause).
+
+ You must have SELECT privilege to a table to read its values
+ (See GRANT/REVOKE statements).
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+WHERE clause</div>
<div class="diff add">+
+ The optional WHERE condition has the general form:
+
+
+WHERE expr cond_op expr [log_op ...]
+
+
+ where cond_op can be one of: =, <, <=, >, >=, <>
+ or a conditional operator like ALL, ANY, IN, LIKE, et cetera
+ and log_op can be one of: AND, OR, NOT.
+ The comparison returns either TRUE or FALSE and all
+ instances will be discarded
+ if the expression evaluates to FALSE.
+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+GROUP BY clause</div>
<div class="diff add">+
+ GROUP BY specifies a grouped table derived by the application
+ of the this clause:
+
+GROUP BY column [, ...]
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+HAVING clause</div>
<div class="diff add">+
+ The optional HAVING condition has the general form:
+
+
+HAVING cond_expr
+
+
+ where cond_expr is the same
+as specified for the WHERE clause.
+
+ HAVING specifies a grouped table derived by the elimination
+ of groups from the result of the previously specified clause
+ that do not meet the cond_expr.
+
+ Each column referenced in cond_expr shall unambiguously
+ reference a grouping column.
+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+ORDER BY clause</div>
<div class="diff add">+
+
+ORDER BY column [ASC | DESC] [, ...]
+
+
+column can be either a column
+name or an ordinal number.
+ The ordinal numbers refers to the ordinal (left-to-right) position
+ of the column. This feature makes it possible to define an ordering
+ on the basis of a column that does not have a proper name.
+ This is never absolutely necessary because it is always possible assign a name
+ to a calculated column using the AS clause, e.g.:
+SELECT title, date_prod + 1 AS newlen FROM films ORDER BY newlen;
+
+
+ The columns in the ORDER BY must appear in the SELECT clause.
+ Thus the following statement is illegal:
+SELECT name FROM distributors ORDER BY code;
+
+
+ Optionally one may add the keyword DESC (descending)
+ or ASC (ascending) after each column name in the ORDER BY clause.
+ If not specified, ASC is assumed by default.
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+UNION clause</div>
<div class="diff add">+
+
+table_query UNION [ALL] table_query
+ [ORDER BY column [ASC | DESC] [, ...] ]
+
+
+where
+ table_query
+ specifies any select expression without an ORDER BY clause.
+
+ The UNION operator specifies a table derived from a Cartesian product.
+ The two tables that represent the direct operands of the UNION must
+ have the same number of columns, and corresponding columns must be
+ of compatible data types.
+
+ By default, the result of UNION does not contain any duplicate rows
+ unless the ALL clause is specified.
+
+Multiple UNION operators in the same SELECT statement are evaluated left to right.
+Note that the ALL keyword is not global in nature, being applied only for the current pair of
+table results.
+
+
+
+
+
</div>
<div class="diff add">+Usage</div>
<div class="diff add">+
+
+ --Join table films with their distributors:
+ --
+ SELECT f.title, f.did, d.name, f.date_prod, f.kind
+ FROM distributors d, films f
+ WHERE f.did = d.did;
+
+ title |did|name | date_prod|kind
+ -------------------------+---+----------------+----------+----------
+ The Third Man |101|British Lion |1949-12-23|Drama
+ The African Queen |101|British Lion |1951-08-11|Romantic
+ Une Femme est une Femme |102|Jean Luc Godard |1961-03-12|Romantic
+ Vertigo |103|Paramount |1958-11-14|Action
+ Becket |103|Paramount |1964-02-03|Drama
+ 48 Hrs |103|Paramount |1982-10-22|Action
+ War and Peace |104|Mosfilm |1967-02-12|Drama
+ West Side Story |105|United Artists |1961-01-03|Musical
+ Bananas |105|United Artists |1971-07-13|Comedy
+ Yojimbo |106|Toho |1961-06-16|Drama
+ There's a Girl in my Soup|107|Columbia |1970-06-11|Comedy
+ Taxi Driver |107|Columbia |1975-05-15|Action
+ Absence of Malice |107|Columbia |1981-11-15|Action
+ Storia di una donna |108|Westward |1970-08-15|Romantic
+ The King and I |109|20th Century Fox|1956-08-11|Musical
+ Das Boot |110|Bavaria Atelier |1981-11-11|Drama
+ Bed Knobs and Broomsticks|111|Walt Disney | |Musical
+
+
+ --sum column "len" of all films group by "kind":
+ --
+ SELECT kind, SUM(len) AS total FROM films GROUP BY kind;
+
+ kind |total
+ ----------+------
+ Action | 07:34
+ Comedy | 02:58
+ Drama | 14:28
+ Musical | 06:42
+ Romantic | 04:38
+
+
+ --sum column length of all films group by "kind"
+ --having total duration < 5 hours:
+ --
+ SELECT kind, SUM(len) AS total
+ FROM films
+ GROUP BY kind
+ HAVING SUM(len) < INTERVAL '5 hour';
+
+ kind |total
+ ----------+------
+ Comedy | 02:58
+ Romantic | 04:38
+
+
+ --The following two examples are identicals:
+ --
+ SELECT * FROM distributors ORDER BY name;
+ SELECT * FROM distributors ORDER BY 2;
+
+ did|name
+ ---+----------------
+ 109|20th Century Fox
+ 110|Bavaria Atelier
+ 101|British Lion
+ 107|Columbia
+ 102|Jean Luc Godard
+ 113|Luso films
+ 104|Mosfilm
+ 103|Paramount
+ 106|Toho
+ 105|United Artists
+ 111|Walt Disney
+ 112|Warner Bros.
+ 108|Westward
+
+
+ --union of table distributors and table actors:
+ -- (only those that begin with letter W):
+ --
+ -- distributors: actors:
+ -- did|name id|name
+ -- ---+------------ --+--------------
+ -- 108|Westward 1|Woody Allen
+ -- 111|Walt Disney 2|Warren Beatty
+ -- 112|Warner Bros. 3|Walter Matthau
+ -- ... ...
+ --
+ --select only distinct rows (without ALL):
+ --
+ SELECT distributors.name
+ FROM distributors
+ WHERE distributors.name LIKE 'W%'
+ UNION
+ SELECT actors.name
+ FROM actors
+ WHERE actors.name LIKE 'W%';
+
+ name
+ --------------
+ Walt Disney
+ Walter Matthau
+ Warner Bros.
+ Warren Beatty
+ Westward
+ Woody Allen
+
+
+
+
+
+
</div>
<div class="diff add">+Compatibility</div>
<div class="diff add">+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+<Acronym>SQL92</Acronym></div>
<div class="diff add">+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+SELECT clause</div>
<div class="diff add">+
+In the
SQL92 standard, the optional keyword "AS" is just noise and can be
+omitted without affecting the meaning.
+The
Postgres parser requires this keyword when
+renaming columns because the type extensibility features lead to parsing ambiguities
+in this context.
+
+In the
SQL92 standard, the new column name specified in an
+"AS" clause may be referenced in GROUP BY and HAVING clauses. This is not currently
+
+
+
+
+
+1998-04-15
+
+
</div>
<div class="diff add">+UNION clause</div>
<div class="diff add">+
+The
SQL92 syntax for UNION allows an additional CORRESPONDING BY clause:
+
+table_query UNION [ALL]
+ [CORRESPONDING [BY (column [,...])]]
+ table_query
+
+
+The CORRESPONDING BY clause is not supported by
Postgres.
+
+
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projects / postgresql.git / commitdiff