-ERROR: <unnamed> referential integrity violation - key referenced from weather not found in cities
+ERROR: insert or update on "weather" violates foreign key constraint "$1"
+DETAIL: Key (city)=(Berkeley) is not present in "cities".
|
adnum
int2
- pg_attribute.attnum
+ pg_attribute.attnum
The number of the column
|
refclassid
oid
- pg_class.oid
+ pg_class.oid
The OID of the system catalog the referenced object is in
|
typbasetype
oid
- pg_type.oid
+ pg_type.oid
If this is a derived type (see typtype),
then typbasetype identifies
- To be able make use of this option the server must be built
+ To make use of this option the server must be built
with SSL support enabled. Furthermore, SSL must be enabled by
enabling the ssl configuration parameter
(see for more information).
-No pg_hba.conf entry for host 123.123.123.123, user andym, database testdb
+FATAL: no pg_hba.conf entry for host "123.123.123.123", user "andym", database "testdb"
This is what you are most likely to get if you succeed in contacting
the server, but it does not want to talk to you. As the message
-Password authentication failed for user 'andym'
+FATAL: Password authentication failed for user "andym"
Messages like this indicate that you contacted the server, and it is
willing to talk to you, but not until you pass the authorization
-FATAL 1: user "andym" does not exist
+FATAL: user "andym" does not exist
The indicated user name was not found.
-FATAL 1: Database "testdb" does not exist in the system catalog.
+FATAL: database "testdb" does not exist
The database you are trying to connect to does not exist. Note that
if you do not specify a database name, it defaults to the database
user name, which may or may not be the right thing.
+
- Note that the server log may contain more information about an
+ The server log may contain more information about an
authentication failure than is reported to the client. If you are
confused about the reason for a failure, check the log.
+
INSERT INTO test VALUES (B'101', B'00');
INSERT INTO test VALUES (B'10', B'101');
-ERROR: Bit string length 2 does not match type BIT(3)
+ERROR: bit string length 2 does not match type bit(3)
INSERT INTO test VALUES (B'10'::bit(3), B'101');
SELECT * FROM test;
-
+
Data Definition
DROP TABLE products;
NOTICE: constraint $1 on table orders depends on table products
-ERROR: Cannot drop table products because other objects depend on it
- Use DROP ... CASCADE to drop the dependent objects too
+ERROR: cannot drop table products because other objects depend on it
+HINT: Use DROP ... CASCADE to drop the dependent objects too.
The error message contains a useful hint: if you do not want to
bother deleting all the dependent objects individually, you can run
specifying CASCADE. Of course, the nature of
the possible dependencies varies with the type of the object. You
can also write RESTRICT instead of
- CASCADE to get the default behavior which is to
+ CASCADE to get the default behavior, which is to
prevent drops of objects that other objects depend on.
-
+
Documentation
- Additionally, a number of plain-text README-type files can be found
- throughout the
PostgreSQL source tree,
+ Additionally, a number of plain-text README files can
+
be found throughout the
PostgreSQL source tree,
documenting various implementation issues.
Reference pages describing SQL commands should contain the
following sections: Name, Synopsis, Description, Parameters,
- Usage, Diagnostics, Notes, Examples, Compatibility, History, See
+ Outputs, Notes, Examples, Compatibility, History, See
Also. The Parameters section is like the Options section, but
there is more freedom about which clauses of the command can be
- listed. The Compatibility section should explain to what extent
+ listed. The Outputs section is only needed if the command returns
+ something other than a default command-completion tag. The Compatibility
+ section should explain to what extent
this command conforms to the SQL standard(s), or to which other
database system it is compatible. The See Also section of SQL
commands should list SQL commands before cross-references to
- Warning. to_char(interval, text)
- is deprecated and should not be used in newly-written code. Will be removed in the next version.
+ Warning: to_char(interval, text)
+ is deprecated and should not be used in newly-written code. It will be removed in the next version.
2 | two
3 | other
-
+
+
+ A CASE expression does not evaluate any subexpressions
+ that are not needed to determine the result. For example, this is a
+ possible way of avoiding a division-by-zero failure:
+SELECT ... WHERE CASE WHEN x <> 0 THEN y/x > 1.5 ELSE false END;
+
+
The COALESCE function returns the first of its
- arguments that is not null. This is often useful to substitute a
+ arguments that is not null. Null is returned only if all arguments
+ are null. This is often useful to substitute a
default value for null values when data is retrieved for display,
for example:
SELECT COALESCE(description, short_description, '(none)') ...
+
+ Like a CASE expression, COALESCE will
+ not evaluate arguments that are not needed to determine the result;
+ that is, arguments to the right of the first non-null argument are
+ not evaluated.
+
|
+
+ array_cat
+ (anyarray, anyarray)
+
+
+ anyarray
+
+ concatenate two arrays, returning NULL
+ for NULL inputs
+
+ array_cat(ARRAY[1,2,3], ARRAY[4,5])
+ {1,2,3,4,5}
+
+ |
+
array_append
(anyarray, anyelement)
|
- array_cat
- (anyarray, anyarray)
+ array_prepend
+ (anyelement, anyarray)
anyarray
- concatenate two arrays, returning NULL
- for NULL inputs
+ append an element to the beginning of an array, returning
+ NULL for NULL inputs
- array_cat(ARRAY[1,2,3], ARRAY[4,5,6])
- {1,2,3,4,5,6}
+ array_prepend(1, ARRAY[2,3])
+ {1,2,3}
|
returns a text representation of array dimension lower and upper bounds,
generating an ERROR for NULL inputs
- array_dims(array[[1,2,3],[4,5,6]])
+ array_dims(array[[1,2,3], [4,5,6]])
[1:2][1:3]
|
|
- array_prepend
- (anyelement, anyarray)
+ array_upper
+ (anyarray, integer)
- anyarray
+ integer
- append an element to the beginning of an array, returning
+ returns upper bound of the requested array dimension, returning
NULL for NULL inputs
- array_prepend(1, ARRAY[2,3])
- {1,2,3}
+ array_upper(ARRAY[1,2,3,4], 1)
+ 4
|
concatenates array elements using provided delimiter, returning
NULL for NULL inputs
- array_to_string(array[1.1,2.2,3.3]::numeric(4,2)[],'~^~')
- 1.10~^~2.20~^~3.30
-
- |
-
-
- array_upper
- (anyarray, integer)
-
-
- integer
-
- returns upper bound of the requested array dimension, returning
- NULL for NULL inputs
-
- array_upper(array_append(ARRAY[1,2,3], 4), 1)
- 4
+ array_to_string(array[1, 2, 3], '~^~')
+ 1~^~2~^~3
|
splits string into array elements using provided delimiter, returning
NULL for NULL inputs
- string_to_array('1.10~^~2.20~^~3.30','~^~')::float8[]
- {1.1,2.2,3.3}
+ string_to_array( 'xx~^~yy~^~zz', '~^~')
+ {xx,yy,zz}
READMEs
- README files are available for some
+ README files are available for most
contributed packages.
play=# VACUUM;
-WARNING: Some databases have not been vacuumed in 1613770184 transactions.
- Better vacuum them within 533713463 transactions,
- or you may have a wraparound failure.
+WARNING: some databases have not been vacuumed in 1613770184 transactions
+HINT: Better vacuum them within 533713463 transactions, or you may have a wraparound failure.
VACUUM
-
PostgreSQL is unable to reuse B-tree index
- pages in certain cases. The problem is that if indexed rows are
- deleted, those index pages can only be reused by rows with similar
- values. For example, if indexed rows are deleted and newly
- inserted/updated rows have much higher values, the new rows can't use
- the index space made available by the deleted rows. Instead, such
- new rows must be placed on new index pages. In such cases, disk
- space used by the index will grow indefinitely, even if
- VACUUM is run frequently.
-
- As a solution, you can use the REINDEX command
- periodically to discard pages used by deleted rows. There is also
- contrib/reindexdb which can reindex an entire database.
+ In some situations it is worthwhile to rebuild indexes periodically
+ with the REINDEX command. (There is also
+ contrib/reindexdb which can reindex an entire database.)
+ However,
PostgreSQL 7.4 has substantially reduced the need+ for this activity compared to earlier releases.
then the serializable transaction will be rolled back with the message
-ERROR: Can't serialize access due to concurrent update
+ERROR: could not serialize access due to concurrent update
because a serializable transaction cannot modify rows changed by
in charge of installing and running the server. A user
could be anyone who is using, or wants to use, any part of the
PostgreSQL system. These terms should not
- be interpreted too narrowly; this documentation set does not have fixed
+ be interpreted too narrowly; this book does not have fixed
presumptions about system administration procedures.
RAISE level 'format' , variable , ...;
- Possible levels are DEBUG (write the message to
- the server log), LOG (write the message to the
- server log with a higher priority), INFO,
- NOTICE and WARNING (write
- the message to the server log and send it to the client, with
- respectively higher priorities), and EXCEPTION
- (raise an error and abort the current transaction). Whether
- messages of a particular priority are reported to the client,
+ Possible levels are DEBUG,
+ LOG, INFO,
+ NOTICE, WARNING,
+ and EXCEPTION.
+ EXCEPTION raises an error and aborts the current
+ transaction; the other levels only generate messages of different
+ priority levels.
+ Whether messages of a particular priority are reported to the client,
written to the server log, or both is controlled by the
log_min_messages and
client_min_messages configuration
In this example, the value of v_job_id will replace the
- % in the string.
+ % in the string:
RAISE NOTICE ''Calling cs_create_job(%)'', v_job_id;
- This example will abort the transaction with the given error message.
+ This example will abort the transaction with the given error message:
RAISE EXCEPTION ''Inexistent ID --> %'', user_id;
Thus, the only thing
PL/pgSQL currently does when it encounters an abort during execution of a
- function or trigger procedure is to write some additional
- NOTICE level log messages telling in which
- function and where (line number and type of statement) this
- happened. The error always stops execution of the function.
+ function or trigger procedure is to add some fields to the message
+ telling in which function and where (line number and type of statement)
+ the error happened. The error always stops execution of the function.
- You can overload function
s in PostgreSQL. This is often used to work - around the lack of default parameters.
+ You can overload function
names in PostgreSQL. This is+ often used to work around the lack of default parameters.
-
+
PL/Python - Python Procedural Language
return args[0]
- where 23456 is the OID of the function.
+ assuming that 23456 is the OID of the function.
- Welcome to
PostgreSQL Tutorial. The
+ Welcome to
the PostgreSQL Tutorial. The
following few chapters are intended to give a simple introduction
to
PostgreSQL, relational database
concepts, and the SQL language to those who are new to any one of
these aspects. We only assume some general knowledge about how to
use computers. No particular Unix or programming experience is
- required. This part is mainly intended to give you a hands-on
+ required. This part is mainly intended to give you some hands-on
experience with important aspects of the
PostgreSQL system. It makes no attempt
to be a complete or thorough treatment of the topics it covers.
-
+
Queries
name must also be given, as in
SELECT tbl1.a, tbl2.a, tbl1.b FROM ...
+
+ When working with multiple tables, it can also be useful to ask for
+ all the columns of a particular table:
+SELECT tbl1.*, tbl2.a FROM ...
(See also .)
smaller
is defined in terms of the
< operator. Similarly, descending order is
determined with the > operator.
+
+ Actually,
PostgreSQL uses the default btree+ operator class for the column's datatype to determine the sort
+ ordering for ASC and DESC. Conventionally,
+ datatypes will be set up so that the < and
+ > operators correspond to this sort ordering,
+ but a user-defined datatype's designer could choose to do something
+ different.
+
+
-
+
Regression Tests
Therefore, we provide a variant comparison file,
horology-no-DST-before-1970.out, which includes
the results to be expected on these systems. To silence the bogus
- failure
message on HPPA platforms, resultmap
- includes
+ failure
message on HPUX platforms,
+ resultmap includes
-horology/hppa=horology-no-DST-before-1970
+horology/.*-hpux=horology-no-DST-before-1970
- which will trigger on any machine for which the output of config.guess
- begins with hppa. Other lines
+ which will trigger on any machine for which the output of
+ config.guess includes -hpux.
+ Other lines
in resultmap select the variant comparison file for other
platforms where it's appropriate.
-FATAL: StreamServerPort: bind() failed: Address already in use
- Is another postmaster already running on port 5432?
- If not, wait a few seconds an retry.
+LOG: could not bind IPv4 socket: Address already in use
+HINT: Is another postmaster already running on port 5432? If not, wait a few seconds and retry.
+FATAL: could not create TCP/IP listen socket
This usually means just what it suggests: you tried to start
another postmaster on the same port where one is already running.
on a reserved port number may draw something like:
$ postmaster -i -p 666
-FATAL: StreamServerPort: bind() failed: Permission denied
- Is another postmaster already running on port 666?
- If not, wait a few seconds an retry.
+LOG: could not bind IPv4 socket: Permission denied
+HINT: Is another postmaster already running on port 666? If not, wait a few seconds and retry.
+FATAL: could not create TCP/IP listen socket
A message like
-IpcMemoryCreate: shmget(key=5440001, size=83918612, 01600) failed: Invalid argument
-FATAL 1: ShmemCreate: cannot create region
+FATAL: could not create shared memory segment: Invalid argument
+DETAIL: Failed syscall was shmget(key=5440001, size=4011376640, 03600).
probably means your kernel's limit on the size of shared memory is
- smaller than the
buffer area
PostgreSQL- is trying to create (83918612 bytes in this example). Or it could
+ smaller than the
work area
PostgreSQL+ is trying to create (4011376640 bytes in this example). Or it could
mean that you do not have System-V-style shared memory support
configured into your kernel at all. As a temporary workaround, you
can try starting the server with a smaller-than-normal number
of buffers ( switch). You will eventually want
to reconfigure your kernel to increase the allowed shared memory
size. You may also see this message when trying to start multiple
- servers on the same machine if their total space requested
+ servers on the same machine, if their total space requested
exceeds the kernel limit.
An error like
-IpcSemaphoreCreate: semget(key=5440026, num=16, 01600) failed: No space left on device
+FATAL: could not create semaphores: No space left on device
+DETAIL: Failed syscall was semget(5440126, 17, 03600).
does not mean you've run out of disk
space. It means your kernel's limit on the number of
psql: could not connect to server: Connection refused
- Is the server running on host server.joe.com and accepting
+ Is the server running on host "server.joe.com" and accepting
TCP/IP connections on port 5432?
This is the generic I couldn't find a server to talk
Alternatively, you'll get this when attempting Unix-domain socket
communication to a local server:
-psql: could not connect to server: Connection refused
+psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
The virtual table pg_settings allows
displaying and updating session run-time parameters. It contains one
row for each configuration parameter; the columns are shown in
- . This form allows the
+ . This table allows the
configuration data to be joined with other tables and have a
selection criteria applied.
There are several ways to shut down the database server. You control
- the type of shutdown by sending different signals to the server
- process.
+ the type of shutdown by sending different signals to the
+ postmaster process.
+
Another response could be this:
-psql: could not connect to server: Connection refused
+createdb: could not connect to database template1: could not connect to server:
+No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
-createdb: database creation failed
This means that the server was not started, or it was not started
where createdb expected it. Again, check the
If you do not have the privileges required to create a database,
you will see the following:
-ERROR: CREATE DATABASE: permission denied
-createdb: database creation failed
+createdb: database creation failed: ERROR: permission denied to create database
Not every user has authorization to create new databases. If
PostgreSQL refuses to create databases
version
----------------------------------------------------------------
- PostgreSQL 7.3devel on i586-pc-linux-gnu, compiled by GCC 2.96
+ PostgreSQL &version; on i586-pc-linux-gnu, compiled by GCC 2.96
(1 row)
mydb=> SELECT current_date;
SELECT @ '-4.5e500' AS "abs";
-ERROR: Input '-4.5e500' is out of range for float8
+ERROR: "-4.5e500" is out of range for float8
SELECT '20' ! AS "factorial";
-ERROR: Unable to identify a postfix operator '!' for type 'text'
- You may need to add parentheses or an explicit cast
+ERROR: operator is not unique: "unknown" !
+HINT: Could not choose a best candidate operator. You may need to add explicit
+typecasts.
This happens because the system can't decide which of the several
possible ! operators should be preferred. We can help
Notice the use of the syntax $1.salary
to select one field of the argument row value. Also notice
how the calling SELECT command uses a table name to denote
- the entire current row of that table as a composite value.
+ the entire current row of that table as a composite value. The table
+ row can alternatively be referenced like this:
+
+SELECT name, double_salary(emp.*) AS dream
+ FROM emp
+ WHERE emp.cubicle ~= point '(2,1)';
+
+ which emphasizes its row nature.
projects / postgresql.git / commitdiff