+|
+
+Parameter
+
+
+Example
+
+
+
+|
+
+user
+
+
+
+
+|
+
+user
+
+
+
+
+|
+
+host
+
+
+
+
+
+
+
+Support for Version 4 will disappear sometime after the production
+release of Version 5 by MIT.
exec sql type
+
exec sql prepare
+
exec sql allocate
+
exec sql free
+
exec sql whenever sqlwarning
+
SQLSTATE
+
--- /dev/null
+
+
A Short History of <ProductName>Postgres</ProductName>
+
+
+
The Berkeley <ProductName>Postgres</ProductName> Project
+
+ Implementation of the
Postgres + initial concepts for the system were presented in
+
+ and the definition of the initial data model
+ appeared in
+.
+The design of the rule system at
+ that time was described in
+.
+The rationale
+ and architecture of the storage manager were detailed in
+.
+
+
+
Postgres has undergone several major releases since
+ then. The first "demoware" system became operational
+ in 1987 and was shown at the 1988
ACM-SIGMOD + Conference. We released Version 1, described in
+,
+ to a few external users in June 1989. In response to a
+ critique of the first rule system
+(),
+the rule
+ system was redesigned
+()
+and Version 2 was
+ released in June 1990 with the new rule system.
+ Version 3 appeared in 1991 and added support for multiple
+ storage managers, an improved query executor, and a
+ rewritten rewrite rule system. For the most part,
+ releases since then have focused on portability and
+ reliability.
+
+
+
Postgres has been used to implement many different
+ research and production applications. These include: a
+ financial data analysis system, a jet engine
+ performance monitoring package, an asteroid tracking
+ database, a medical information database, and several
+ geographic information systems.
+ used as an educational tool at several universities.
+ Finally,
+
Illustra Information Technologies+(since merged into
+
+ picked up
+ the code and commercialized it.
+
Postgres became the primary data manager
+ for the
+ scientific computing project in late 1992.
+ Furthermore, the size of the external user community
+ nearly doubled during 1993. It became increasingly
+ obvious that maintenance of the prototype code and
+ support was taking up large amounts of time that should
+ have been devoted to database research. In an effort
+ to reduce this support burden, the project officially
+ ended with Version 4.2.
+
+
+
+
+
<ProductName>Postgres95</ProductName>
+
+In 1994,
+and
+added a SQL language interpreter to
Postgres,
+and the code was subsequently released to
+the Web to find its own way in the world.
+
Postgres95 was a public-domain, open source descendant
+of this original Berkeley code.
+
+
+
Postgres95 is a derivative of the last official release
+of
Postgres (version 4.2). The code is now completely
+ ANSI C and the code size has been trimmed by 25%. There
+ are a lot of internal changes that improve performance
+and code maintainability.
+
Postgres95 v1.0.x runs about 30-50%
+ faster on the Wisconsin Benchmark compared to v4.2.
+ Apart from bug fixes, these are the major enhancements:
+
+
+
+ The query language
Postquel has been replaced with
+
SQL (implemented in the server). We do not yet support
+ subqueries (which can be imitated with user defined
+
SQL functions). Aggregates have been
+ re-implemented. We also added support for ``GROUP BY''.
+ The
libpq interface is still available for
C + programs.
+
+
+
+ In addition to the monitor program, we provide a new
+ program (
psql) which supports
GNU readline.
+
+
+
+ We added a new front-end library, libpgtcl, that
+ supports
Tcl-based clients. A sample shell,
+ pgtclsh, provides new Tcl commands to interface
tcl+ programs with the
Postgres95 backend.
+
+
+
+ The large object interface has been overhauled. We
+ kept Inversion large objects as the only mechanism
+ for storing large objects. (This is not to be
+ confused with the Inversion file system which has been
+ removed.)
+
+
+
+ The instance-level rule system has been removed.
+ Rules are still available as rewrite rules.
+
+
+
+ A short tutorial introducing regular
SQL features as
+ well as those of ours is distributed with the source
+ code.
+
+
+
+
GNU make (instead of
BSD make) is used for the
+ build. Also,
Postgres95 can be compiled with an
+ unpatched
gcc (data alignment of doubles has been
+ fixed).
+
+
+
+
+
+
+
+
<ProductName>PostgreSQL</ProductName>
+
+By 1996, it became clear that the name Postgres95
would not stand
+the test of time. A new name,
PostgreSQL,
+was chosen to reflect the
+relationship between original
Postgres +and the more recent
+versions with
SQL capability.
+At the same time, the version numbering
+was reset to start at 6.0,
+putting the numbers back into the sequence originally begun by
+
+The emphasis on development for the v1.0.x releases of
+was on stabilizing the backend code.
+With the v6.x series of
PostgreSQL,
+the emphasis has shifted from
+identifying and understanding existing problems in the backend
+to augmenting features and capabilities, although
+work continues in all areas.
+
+Major enhancements include:
+
+
+
+Important backend features, including subselects, defaults,
+constraints, and triggers, have been implemented.
+
+
+
+Additional
SQL92-compliant language features have been added,
+ including primary keys, quoted identifiers, literal string type coersion,
+type casting, and binary and hexadecimal integer input.
+
+
+
+Built-in types have been improved, including new wide-range date/time types
+and additional geometric type support.
+
+
+
+Overall backend code speed has been increased by approximately 20-40%,
+and backend startup time has decreased 80% since v6.0 was released.
+
+
+
+
+
+
+
\ No newline at end of file
--- /dev/null
+
+
Resources
+
+This manual set is organized into several parts:
+
+
+
+Tutorial
+
+An introduction for new users. Does not cover advanced features.
+
+
+
+
+
+User's Guide
+
+General information for users, including available commands and data types.
+
+
+
+
+
+Programmer's Guide
+
+Advanced information for application programmers. Topics include
+type and function extensibility, library interfaces, and application design issues.
+
+
+
+
+
+Administrator's Guide
+
+Installation and management information. List of supported machines.
+
+
+
+
+
+Developer's Guide
+
+Information for
Postgres developers. This is intended
+for those who are contributing to the
Postgres+project; application development information should appear in the Programmer's Guide.
+
+
+
+
+
+Reference Manual
+
+Detailed reference information on command syntax.
+At the moment, this manual is very sparse, but eventually should contain
+information similar to that in the man pages.
+
+
+
+
+
+In addition to this manual set, there are other resources to help you with
+
Postgres installation and use:
+
+
+
+man pages
+
+The man pages have general information on command syntax.
+
+
+
+
+
+FAQs
+
+The Frequently Asked Questions (FAQ) documents address both general issues
+and some platform-specific issues.
+
+
+
+
+
+READMEs
+
+README files are available for some contributed packages.
+
+
+
+
+
+Web Site
+
+The
Postgres web site has some information+not appearing in the distribution. There is a
mhonarc catalog of mailing list traffic
+which is a rich resource for many topics.
+
+
+
+
+
+Mailing Lists
+
+mailing list is a good place to have user questions answered. Other mailing lists are available; consult
+the web page for details.
+
+
+
+
+
+Yourself!
+
+
Postgres is an open source product.
+As such, it depends on the user community for
+ongoing support. As you begin to use
Postgres,
+you will rely on others
+for help, either through the documentation or through the mailing lists.
+Consider contributing your
+knowledge back. If you learn something which is not in the documentation,
+write it up and contribute it.
+If you add features to the code, contribute it.
+Even those without a lot of experience can provide
+corrections and minor changes in the documentation, and that is a good way to start.
+The
+mailing list is the place to get going.
+
+
+
+
+
+
--- /dev/null
+
+
Introduction
+
+ This document is the Administrator's Manual for the
+ database management system, originally developed at the University
+ of California at Berkeley.
+
+ led by Professor Michael Stonebraker, was sponsored by the
+ Defense Advanced Research Projects Agency (
DARPA), the
+ Army Research Office (
ARO), the National Science
+ Foundation (
NSF), and ESL, Inc.
+
+
+¬ation;
+
+&legal;
+
+
This document is the programmer's manual for the
database management system, originally developed at the University
- of California at Berkeley.
PostgreSQL is based on
+ of California at Berkeley.
+
The first part of this manual
- explains the
-
Postgres approach to extensibility and describe how
- users can extend
Postgres by adding user-defined types,
- operators, aggregates, and both query language and programming language functions.
+approach to extensibility and describe how
+ users can extend
Postgres +by adding user-defined types,
+ operators, aggregates, and both query language and programming
+language functions.
After an extremely brief
overview of the
Postgres rule system, we discuss
the trigger and SPI interfaces.
- The manual concludes with a detailed description of the programming interfaces and
+ The manual concludes with a detailed description of
+the programming interfaces and
support libraries for various languages.
We assume proficiency with UNIX and C programming.
-
-
Copyrights and Trademarks
-
-
PostgreSQL is copyright (C) 1996-8 by the PostgreSQL Global Development Group,
-and is distributed under the terms of the Berkeley license.
-
-
Postgres95 is copyright (C) 1994-5 by the Regents of the University of California.
-Permission to use, copy, modify, and distribute this software and its documentation
-for any purpose, without fee, and without a written agreement is hereby granted,
-provided that the above copyright notice and this paragraph and the following two
-paragraphs appear in all copies.
-
-In no event shall the University of California be liable to
-any party for direct, indirect, special, incidental, or consequential
-damages, including lost profits, arising out of the use of this
-software and its documentation, even if the University of California
-has been advised of the possibility of such damage.
-
-The University of California specifically disclaims any
-warranties, including, but not limited to, the implied warranties
-of merchantability and fitness for a particular purpose.
-The software provided hereunder is on an "as-is" basis, and
-the University of California has no obligations to provide
-maintainance, support, updates, enhancements, or modifications.
-
+¬ation;
-
UNIX is a trademark of X/Open, Ltd. Sun4, SPARC, SunOS
-and Solaris are trademarks of Sun Microsystems, Inc. DEC,
-DECstation, Alpha AXP and ULTRIX are trademarks of Digital
-Equipment Corp. PA-RISC and HP-UX are trademarks of
-Hewlett-Packard Co. OSF/1 is a trademark of the Open
-Software Foundation.
-
+&legal;
This document is the user manual for the
database management system, originally developed at the University
- of California at Berkeley.
PostgreSQL is based on
+ of California at Berkeley.
+
- led by Professor Michael Stonebraker, has been sponsored by the
+ led by Professor Michael Stonebraker, was sponsored by the
Defense Advanced Research Projects Agency (
DARPA), the
Army Research Office (
ARO), the National Science
Foundation (
NSF), and ESL, Inc.
it is firmly in the relational database world. In fact, some commercial databases
have recently incorporated features pioneered by
Postgres.
-
-
-
-
A Short History of <ProductName>Postgres</ProductName>
-
-
-
The Berkeley <ProductName>Postgres</ProductName> Project
-
- Implementation of the
Postgres DBMS began in 1986. The
- initial concepts for the system were presented in
-
-[STON86]
- and the definition of the initial data model
- appeared in
-
-[ROWE87].
-The design of the rule system at
- that time was described in
-
-[STON87a].
-The rationale
- and architecture of the storage manager were detailed in
-
-[STON87b].
-
-
-
Postgres has undergone several major releases since
- then. The first "demoware" system became operational
- in 1987 and was shown at the 1988
ACM-SIGMOD - Conference. We released Version 1, described in
-
-[STON90a],
- to a few external users in June 1989. In response to a
- critique of the first rule system
-
-([STON89]),
-the rule
- system was redesigned
-
-([STON90b])
-and Version 2 was
- released in June 1990 with the new rule system.
- Version 3 appeared in 1991 and added support for multiple
- storage managers, an improved query executor, and a
- rewritten rewrite rule system. For the most part,
- releases since then have focused on portability and
- reliability.
-
-
-
Postgres has been used to implement many different
- research and production applications. These include: a
- financial data analysis system, a jet engine
- performance monitoring package, an asteroid tracking
- database, a medical information database, and several
- geographic information systems.
Postgres has also been
- used as an educational tool at several universities.
- Finally,
Illustra Information Technologies picked up- the code and commercialized it.
-
Postgres became the primary data manager for the
- scientific computing project in late 1992.
- Furthermore, the size of the external user community
- nearly doubled during 1993. It became increasingly
- obvious that maintenance of the prototype code and
- support was taking up large amounts of time that should
- have been devoted to database research. In an effort
- to reduce this support burden, the project officially
- ended with Version 4.2.
-
-
-
-
-
<ProductName>Postgres95</ProductName>
-
-In 1994,
-and
-added a SQL language interpreter to
Postgres, and the code was subsequently released to
-the Web to find its own way in the world.
Postgres95 was a public-domain, open source descendant
-of this original Berkeley code.
-
-
-
Postgres95 is a derivative of the last official release
- of
Postgres (version 4.2). The code is now completely
- ANSI C and the code size has been trimmed by 25%. There
- are a lot of internal changes that improve performance
- and code maintainability.
Postgres95 v1.0.x runs about 30-50%
- faster on the Wisconsin Benchmark compared to v4.2.
- Apart from bug fixes, these are the major enhancements:
-
-
-
- The query language
Postquel has been replaced with
-
SQL (implemented in the server). We do not yet support
- subqueries (which can be imitated with user defined
-
SQL functions). Aggregates have been
- re-implemented. We also added support for ``GROUP BY''.
- The
libpq interface is still available for
C - programs.
-
-
-
- In addition to the monitor program, we provide a new
- program (
psql) which supports
GNU readline.
-
-
-
- We added a new front-end library, libpgtcl, that
- supports
Tcl-based clients. A sample shell,
- pgtclsh, provides new Tcl commands to interface
tcl- programs with the
Postgres95 backend.
-
-
-
- The large object interface has been overhauled. We
- kept Inversion large objects as the only mechanism
- for storing large objects. (This is not to be
- confused with the Inversion file system which has been
- removed.)
-
-
-
- The instance-level rule system has been removed.
- Rules are still available as rewrite rules.
-
-
-
- A short tutorial introducing regular
SQL features as
- well as those of ours is distributed with the source
- code.
-
-
-
-
GNU make (instead of
BSD make) is used for the
- build. Also,
Postgres95 can be compiled with an
- unpatched
gcc (data alignment of doubles has been
- fixed).
-
-
-
-
-
-
-
-
<ProductName>PostgreSQL</ProductName>
-
-By 1996, it became clear that the name Postgres95
would not stand
-the test of time. A new name,
PostgreSQL, was chosen to reflect the
-relationship between original
Postgres and the more recent
-versions with
SQL capability. At the same time, the version numbering
-was reset to start at 6.0, putting the numbers back into the sequence originally begun by
-
-The emphasis on development for the v1.0.x releases of
Postgres95-was on stabilizing the backend code.
-With the v6.x series of
PostgreSQL, the emphasis has shifted from
-identifying and understanding existing problems in the backend to augmenting features and capabilities, although
-work continues in all areas.
-
-Major enhancements include:
-
-
-
-Important backend features, including subselects, defaults, constraints, and triggers, have been implemented.
-
-
-
-Additional
SQL92-compliant language features have been added,
- including primary keys, quoted identifiers, literal string type coersion, type casting,
- and binary and hexadecimal integer input.
-
-
-
-Built-in types have been improved, including new wide-range date/time types and additional geometric type support.
-
-
-
-Overall backend code speed has been increased by approximately 20%, and backend startup time has decreased 80%.
-
-
-
-
-
-
-
-
About This Release
-
- From now on, We will use
Postgres to mean
PostgreSQL.
-
-
PostgreSQL is available without cost. This manual
- describes version 6.3 of
PostgreSQL.
-
-Check the Administrator's Guide for a list of currently supported machines. In general,
-
PostgreSQL is portable to any Unix/Posix-compatible system
-with full libc library support.
-
-
-
Resources
+&history;
-This manual set is organized into several parts:
+&about;
-
-
-Tutorial
-
-An introduction for new users. Does not cover advanced features.
-
-
-
+&info;
-
-User's Guide
-
-General information for users, including available commands and data types.
-
-
-
-
-
-Programmer's Guide
-
-Advanced information for application programmers. Topics include
-type and function extensibility, library interfaces, and application design issues.
-
-
-
-
-
-Administrator's Guide
-
-Installation and management information. List of supported machines.
-
-
-
-
-
-Developer's Guide
-
-Information for
Postgres developers. This is intended
-for those who are contributing to the
Postgres-project; application development information should appear in the Programmer's Guide.
-
-
-
-
-
-Reference Manual
-
-Detailed reference information on command syntax.
-At the moment, this manual is very sparse, but eventually should contain
-information similar to that in the man pages.
-
-
-
-
-
-In addition to this manual set, there are other resources to help you with
-
Postgres installation and use:
-
-
-
-man pages
-
-The man pages have general information on command syntax.
-
-
-
-
-
-FAQs
-
-The Frequently Asked Questions (FAQ) documents address both general issues
-and some platform-specific issues.
-
-
-
-
-
-READMEs
-
-README files are available for some contributed packages.
-
-
-
-
-
-Web Site
-
-The
Postgres web site has some information-not appearing in the distribution. There is a
mhonarc catalog of mailing list traffic
-which is a rich resource for many topics.
-
-
-
-
-
-Mailing Lists
-
-mailing list is a good place to have user questions answered. Other mailing lists are available; consult
-the web page for details.
-
-
-
-
-
-Yourself!
-
-
Postgres is an open source product. As such, it depends on the user community for
-ongoing support. As you begin to use
Postgres, you will rely on others
-for help, either through the documentation or through the mailing lists. Consider contributing your
-knowledge back. If you learn something which is not in the documentation, write it up and contribute it.
-If you add features to the code, contribute it. Even those without a lot of experience can provide
-corrections and minor changes in the documentation, and that is a good way to start.
-The
Postgres Documentation-mailing list is the place to get going.
-
-
-
-
-
-
-
-
-
Copyrights and Trademarks
-
-
PostgreSQL is copyright (C) 1996-8 by the PostgreSQL Global Development Group,
-and is distributed under the terms of the Berkeley license.
-
-
Postgres95 is copyright (C) 1994-5 by the Regents of the University of California.
-Permission to use, copy, modify, and distribute this software and its documentation
-for any purpose, without fee, and without a written agreement is hereby granted,
-provided that the above copyright notice and this paragraph and the following two
-paragraphs appear in all copies.
-
-In no event shall the University of California be liable to
-any party for direct, indirect, special, incidental, or consequential
-damages, including lost profits, arising out of the use of this
-software and its documentation, even if the University of California
-has been advised of the possibility of such damage.
-
-The University of California specifically disclaims any
-warranties, including, but not limited to, the implied warranties
-of merchantability and fitness for a particular purpose.
-The software provided hereunder is on an "as-is" basis, and
-the University of California has no obligations to provide
-maintainance, support, updates, enhancements, or modifications.
-
-
-
UNIX is a trademark of X/Open, Ltd. Sun4, SPARC, SunOS
-and Solaris are trademarks of Sun Microsystems, Inc. DEC,
-DECstation, Alpha AXP and ULTRIX are trademarks of Digital
-Equipment Corp. PA-RISC and HP-UX are trademarks of
-Hewlett-Packard Co. OSF/1 is a trademark of the Open
-Software Foundation.
-
+&legal;
--- /dev/null
+
+
Copyrights and Trademarks
+
+
PostgreSQL is copyright (C) 1996-8
+by the PostgreSQL Global Development Group,
+and is distributed under the terms of the Berkeley license.
+
+
Postgres95 is copyright (C) 1994-5
+by the Regents of the University of California.
+Permission to use, copy, modify, and distribute this software and its documentation
+for any purpose, without fee, and without a written agreement is hereby granted,
+provided that the above copyright notice and this paragraph and the following two
+paragraphs appear in all copies.
+
+In no event shall the University of California be liable to
+any party for direct, indirect, special, incidental, or consequential
+damages, including lost profits, arising out of the use of this
+software and its documentation, even if the University of California
+has been advised of the possibility of such damage.
+
+The University of California specifically disclaims any
+warranties, including, but not limited to, the implied warranties
+of merchantability and fitness for a particular purpose.
+The software provided hereunder is on an "as-is" basis, and
+the University of California has no obligations to provide
+maintainance, support, updates, enhancements, or modifications.
+
+
+
UNIX is a trademark of X/Open, Ltd. Sun4, SPARC, SunOS
+and Solaris are trademarks of Sun Microsystems, Inc. DEC,
+DECstation, Alpha AXP and ULTRIX are trademarks of Digital
+Equipment Corp. PA-RISC and HP-UX are trademarks of
+Hewlett-Packard Co. OSF/1 is a trademark of the Open
+Software Foundation.
+
--- /dev/null
+
+
Terminology
+
+In the following documentation,
+site
+may be interpreted as the host machine on which
+Since it is possible to install more than one set of
+databases on a single host, this term more precisely denotes any
+particular set of installed
+
Postgres binaries and databases.
+
+The
+is the user named postgres
+binaries and database files. As the database super-user, all
+protection mechanisms may be bypassed and any data accessed
+arbitrarily.
+In addition, the
Postgres super-user is allowed to execute
+some support programs which are generally not available to all users.
+Note that the
Postgres super-user is
+not
+the same as the Unix super-user (root),
+and should have a non-zero userid for security reasons.
+
+The
+database base administrator
+or
DBA, is the person who is responsible for installing
+
Postgres with mechanisms to
+enforce a security policy for a site. The DBA can add new users by
+the method described below
+and maintain a set of template databases for use by
+
+is the process that acts as a clearing-house for requests
+Frontend applications connect to the
postmaster,
+which keeps tracks of any system errors and communication between the
+backend processes. The
postmaster+can take several command-line arguments to tune its behavior.
+However, supplying arguments is necessary only if you intend to run multiple
+sites or a non-default site.
+
+(the actual executable program
postgres) may be executed
+directly from the user shell by the
+(with the database name as an argument). However,
+doing this bypasses the shared buffer pool and lock table associated
+with a postmaster/site, therefore this is not recommended in a multiuser
+site.
+
+
+
Notation
+
+...
at the front of a file name is used to represent the
+path to the
Postgres super-user's home directory.
+Anything in brackets
+[
and ]
) is optional. Anything in braces
+({
and }
) can be repeated 0 or more times.
+Parentheses ((
and )
) are used to group boolean
+expressions. |
is the boolean operator OR.
+
+
\ No newline at end of file
1998-08-25
-
<span class="marked"><acronym>ODBC</acronym></span> Interface
+
<span class="marked">ODBC</span> Interface
+
+
Lexical Precedence
+
+Operators have a precedence which is currently hardcoded into the parser.
+Most operators have the same precedence and are non-associative. This may lead
+to non-intuitive behavior; for example the boolean operators "<" and ">"
+have a different precedence that the boolean operators "<=" and ">=".
+
+
</div>
<div class="diff add">+Operator Ordering (decreasing precedence)</div>
<div class="diff add">+
+
+
+
+|
+
+Element
+
+Precedence
+
+Description
+
+
+
+|
+
+UNION
+
+left
+
+SQL select construct
+|
+
+::
+
+
+
+|
+
+[ ]
+
+left
+
+array delimiters
+
+|
+
+.
+
+left
+
+table/column delimiter
+
+|
+
+-
+
+right
+
+unary minus
+
+|
+
+;
+
+left
+
+statement termination, logarithm
+
+|
+
+:
+
+right
+
+exponentiation
+
+|
+
+|
+
+left
+
+start of interval
+
+|
+
+* /
+
+left
+
+multiplication, division
+
+|
+
++ -
+
+left
+
+addition, subtraction
+
+|
+
+IS
+
+
+test for TRUE, FALSE, NULL
+|
+
+ISNULL
+
+
+test for NULL
+
+|
+
+NOTNULL
+
+
+test for NOT NULL
+
+|
+
+(all other operators)
+
+
+native and user-defined
+
+|
+
+IN
+
+
+set membership
+
+|
+
+BETWEEN
+
+
+containment
+
+|
+
+LIKE
+
+
+string pattern matching
+
+|
+
+< >
+
+
+boolean inequality
+
+|
+
+=
+
+right
+
+equality
+
+|
+
+NOT
+
+right
+
+negation
+
+|
+
+AND
+
+left
+
+logical intersection
+
+|
+
+OR
+
+left
+
+logical union
+
+
+
+
General Operators
%allfiles;
+
+
Installation and maintenance information.
+&intro-ag;
&ports;
&install;
&start-ag;
-
+
+
-
+
+
+
+
+
+
+
]>
-
+
-
PostgreSQL is copyright (C) 1998 by the Postgres Global Development Group.
+
PostgreSQL is copyright (C) 1998
+by the Postgres Global Development Group.
-This chapter must go into depth on each area of the query language. Currently a copy of the tutorial.
+This chapter must go into depth on each area of the query language.
+Currently a copy of the tutorial.
- thomas 1998-01-12
has many extensions such as an extensible type system,
inheritance, functions and production rules. Those are
- features carried over from the original
Postgres query
- language,
PostQuel. This section provides an overview
- of how to use
Postgres SQL to perform simple operations.
+ features carried over from the original
Postgres +query
+This section provides an overview
+ of how to use
Postgres SQL+ to perform simple operations.
This manual is only intended to give you an idea of our
flavor of
SQL and is in no way a complete tutorial on
SQL. Numerous books have been written on
SQL. For
- instance, consult <Ulink url="refs.html#MELT93">[MELT93]> or
- <Ulink url="refs.html#DATE93">[DATE93]>. You should also
- be aware that some features
are not part of the ANSI>- standard.
+ instance, consult <xref linkend="MELT93" endterm="MELT93-full"> or
+ <xref linkend="DATE97" endterm="DATE97-full">. You should also
+ be aware that some features
of Postgres>+
are not part of the ANSI standard.
Concepts
- The fundamental notion in
Postgres is that of a class,
+ The fundamental notion in
Postgres +is that of a class,
which is a named collection of object instances. Each
instance has the same collection of named attributes,
and each attribute is of a specific type. Furthermore,
- each instance has a permanent
object identifier (
OID)
+ each instance has a permanent object
that is unique throughout the installation. Because
SQL syntax refers to tables, we will use the terms
table and class interchangeably.
Likewise, an
SQL row is an
-
instance and
SQL columns+columns
are attributes.
As previously discussed, classes are grouped into
databases, and a collection of databases managed by a
--- /dev/null
+
+
Runtime Environment
+
+This chapter outlines the interaction between
Postgres and
+the operating system.
+
+
+
Using <Productname>Postgres</Productname> from Unix
+
+All
Postgres commands that are executed
+directly from a Unix shell are
+found in the directory .../bin
. Including this directory in
+your search path will make executing the commands easier.
+
+A collection of system catalogs exist at each site. These include a
+class (pg_user) that contains an instance for each valid
+
Postgres user. The instance specifies a set of
+
Postgres privileges, such as
+the ability to act as
Postgres super-user,
+ the ability to create/destroy
+databases, and the ability to update the system catalogs. A Unix
+user cannot do anything with
Postgres +until an appropriate instance is
+installed in this class. Further information on the system catalogs
+is available by running queries on the appropriate classes.
+
+
+
System Layout
+
+
+
<ProductName>Postgres</ProductName> file layout
+
+
+
+
+shows how the
Postgres distribution is laid
+ out when installed in the default way. For simplicity,
+ we will assume that
Postgres+ has been installed in the
+ directory /usr/local/pgsql. Therefore, wherever
+ you see the directory /usr/local/pgsql you should
+ substitute the name of the directory where
+ actually installed.
+ All
Postgres commands are installed
+ in the directory
+ /usr/local/pgsql/bin. Therefore, you should add
+ this directory to your shell command path. If you use
+ a variant of the Berkeley C shell, such as csh or tcsh,
+ you would add
+set path = ( /usr/local/pgsql/bin path )
+
+ in the .login file in your home directory. If you use
+ a variant of the Bourne shell, such as sh, ksh, or
+ bash, then you would add
+PATH=/usr/local/pgsql/bin PATH
+export PATH
+
+ to the .profile file in your home directory.
+ From now on, we will assume that you have added the
+
Postgres bin directory to your path.
+ In addition, we
+ will make frequent reference to "setting a shell
+ variable" or "setting an environment variable" throughout
+ this document. If you did not fully understand the
+ last paragraph on modifying your search path, you
+ should consult the UNIX manual pages that describe your
+ shell before going any further.
+
+
+If you have not set things up in the
+default way, you may have some more work to do.
+For example, if the database server machine is a remote machine, you
+will need to set the PGHOST environment variable to the name
+of the database server machine. The environment variable
+PGPORT may also have to be set. The bottom line is this: if
+you try to start an application program and it complains
+that it cannot connect to the
postmaster,
+you must go back and make sure that your
+environment is properly set up.
+
+
+
--- /dev/null
+
+
Security
+
+
+
+
User Authentication
+
+Authentication
+is the process by which the backend server and
+ensure that the user requesting access to data is in fact who he/she
+claims to be.
+All users who invoke
Postgres are checked against the
+contents of the pg_user class to ensure that they are
+authorized to do so. However, verification of the user's actual
+identity is performed in a variety of ways:
+
+
+
+
+From the user shell
+
+
+A backend server started from a user shell notes the user's (effective)
+user-id before performing a
+setuid
+to the user-id of user postgres.
+The effective user-id is used
+as the basis for access control checks. No other authentication is
+conducted.
+
+
+
+From the network
+
+
+If the
Postgres system is built as distributed,
+ access to the Internet TCP port of the
+process is available to anyone. The DBA configures the pg_hba.conf file
+in the PGDATA directory to specify what authentication system is to be used
+according to the host making the connection and which database it is
+connecting to. See pg_hba.conf(5)
+ for a description of the authentication
+systems available. Of course, host-based authentication is not fool-proof in
+Unix, either. It is possible for determined intruders to also
+masquerade the origination host. Those security issues are beyond the
+
+
+
+
+
+
Access Control
+
+
Postgres provides mechanisms to allow users
+to limit the access to their data that is provided to other users.
+
+
+
+
+Database superusers
+
+
+Database super-users (i.e., users who have pg_user.usesuper
+set) silently bypass all of the access controls described below with
+two exceptions: manual system catalog updates are not permitted if the
+user does not have pg_user.usecatupd set, and destruction of
+system catalogs (or modification of their schemas) is never allowed.
+
+
+
+Access Privilege
+
+
+The use of access privilege to limit reading, writing and setting
+of rules on classes is covered in
+grant/revoke(l).
+
+
+
+Class removal and schema modification
+
+
+Commands that destroy or modify the structure of an existing class,
+such as alter,
+drop table,
+and
+drop index,
+only operate for the owner of the class. As mentioned above, these
+operations are never
+permitted on system catalogs.
+
+
+
+
+
Functions and Rules
+
+Functions and rules allow users to insert code into the backend server
+that other users may execute without knowing it. Hence, both
+mechanisms permit users to trojan horse
+others with relative impunity. The only real protection is tight
+control over who can define functions (e.g., write to relations with
+SQL fields) and rules. Audit trails and alerters on
+pg_class, pg_user
+ and pg_group are also recommended.
+
+
+
Functions
+
+Functions written in any language except SQL
+run inside the backend server
+process with the permissions of the user postgres (the
+backend server runs with its real and effective user-id set to
+postgres. It is possible for users to change the server's
+internal data structures from inside of trusted functions. Hence,
+among many other things, such functions can circumvent any system
+access controls. This is an inherent problem with user-defined C functions.
+
+
+
Rules
+
+Like SQL functions, rules always run with the identity and
+permissions of the user who invoked the backend server.
+
+
+
</div>
<div class="diff add">+Caveats</div>
<div class="diff add">+
+
+There are no plans to explicitly support encrypted data inside of
+(though there is nothing to prevent users from encrypting
+data within user-defined functions). There are no plans to explicitly
+support encrypted network connections, either, pending a total rewrite
+of the frontend/backend protocol.
+User names, group names and associated system identifiers (e.g., the
+contents of pg_user.usesysid) are assumed to be unique
+throughout a database. Unpredictable results may occur if they are
+not.
+
+
\ No newline at end of file
- - thomas 1998-02-24
-->
-
-
Runtime Environment
-
-
-
<ProductName>Postgres</ProductName> file layout
-
-
-
-
-shows how the
Postgres distribution is laid
- out when installed in the default way. For simplicity,
- we will assume that
Postgres has been installed in the
- directory /usr/local/pgsql. Therefore, wherever
- you see the directory /usr/local/pgsql you should
- substitute the name of the directory where
Postgres is
- actually installed.
- All
Postgres commands are installed in the directory
- /usr/local/pgsql/bin. Therefore, you should add
- this directory to your shell command path. If you use
- a variant of the Berkeley C shell, such as csh or tcsh,
- you would add
-set path = ( /usr/local/pgsql/bin path )
-
- in the .login file in your home directory. If you use
- a variant of the Bourne shell, such as sh, ksh, or
- bash, then you would add
-PATH=/usr/local/pgsql/bin PATH
-export PATH
-
- to the .profile file in your home directory.
- From now on, we will assume that you have added the
-
Postgres bin directory to your path. In addition, we
- will make frequent reference to "setting a shell
- variable" or "setting an environment variable" throughout
- this document. If you did not fully understand the
- last paragraph on modifying your search path, you
- should consult the UNIX manual pages that describe your
- shell before going any further.
-
-
-If your site administrator has not set things up in the
-default way, you may have some more work to do. For example, if the database server machine is a remote machine, you
-will need to set the
PGHOST environment variable to the name
-of the database server machine. The environment variable
-
PGPORT may also have to be set. The bottom line is this: if
-you try to start an application program and it complains
-that it cannot connect to the
postmaster, you should immediately consult your site administrator to make sure that your
-environment is properly set up.
-
-
-
-
Locale Support
-
-
-Written by Oleg Bartunov.
- for additional information on locale and Russian language support.
-
-
-
-While doing a project for a company in Moscow, Russia, I encountered the problem that postgresql had no
-support of national alphabets. After looking for possible workarounds I decided to develop support of locale myself.
-I'm not a C-programer but already had some experience with locale programming when I work with perl
-(debugging) and glimpse. After several days of digging through
- the
Postgres source tree I made very minor corections to
-src/backend/utils/adt/varlena.c and src/backend/main/main.c and got what I needed! I did support only for
-LC_CTYPE and LC_COLLATE, but later LC_MONETARY was added by others. I got many
-messages from people about this patch so I decided to send it to developers and (to my surprise) it was
-incorporated into postgresql distribution.
-
- People often complain that locale doesn't work for them. There are several common mistakes:
-
-
-
- Didn't properly configure postgresql before compilation.
- You must run configure with --enable-locale option to enable locale support.
- Didn't setup environment correctly when starting postmaster.
- You must define environment variables $LC_CTYPE and $LC_COLLATE before running postmaster
- because backend gets information about locale from environment. I use following shell script
- (runpostgres):
-
- #!/bin/sh
-
- export LC_CTYPE=koi8-r
- export LC_COLLATE=koi8-r
- postmaster -B 1024 -S -D/usr/local/pgsql/data/ -o '-Fe'
-
-
- and run it from rc.local as
-
- /bin/su - postgres -c "/home/postgres/runpostgres"
-
-
-
-
-
- Broken locale support in OS (for example, locale support in libc under Linux several times has changed
- and this caused a lot of problems). Latest perl has also support of locale and if locale is broken perl -v will
- complain something like:
-
- 8:17[mira]:~/WWW/postgres>setenv LC_CTYPE not_exist
- 8:18[mira]:~/WWW/postgres>perl -v
- perl: warning: Setting locale failed.
- perl: warning: Please check that your locale settings:
- LC_ALL = (unset),
- LC_CTYPE = "not_exist",
- LANG = (unset)
- are supported and installed on your system.
- perl: warning: Falling back to the standard locale ("C").
-
-
-
-
-
- Wrong location of locale files!
-
- Possible locations include: /usr/lib/locale (Linux, Solaris), /usr/share/locale (Linux), /usr/lib/nls/loc (DUX 4.0)
- Check man locale to find the correct location.
-Under Linux I did a symbolic link between /usr/lib/locale and
- /usr/share/locale to be sure that the next libc will not break my locale.
-
-
-
-
-
-
What are the Benefits?
-
-You can use ~* and order by operators for strings contain characters from national alphabets. Non-english users
-definitely need that. If you won't use locale stuff just undefine the USE_LOCALE variable.
-
-
-
What are the Drawbacks?
-
-There is one evident drawback of using locale - it's speed! So, use locale only if you really need it.
-
-
-
Starting <Application>postmaster</Application>
- Nothing can happen to a database unless the
postmaster+ Nothing can happen to a database unless the
process is running. As the site administrator, there
are a number of things you should remember before
- starting the
postmaster. These are discussed in the
- section of this manual titled, "Administering Postgres."
+ starting the
postmaster.
+These are discussed in the installation and configuration sections
+of this manual.
However, if
Postgres has been installed by following
the installation instructions exactly as written, the
following simple command is all you should
% postmaster
- The
postmaster occasionally prints out messages which
+ The
postmaster occasionally prints out
+messages which
are often helpful during troubleshooting. If you wish
- to view debugging messages from the
postmaster, you can
+ to view debugging messages from the
postmaster,
+you can
start it with the -d option and redirect the output to
the log file:
% postmaster -S
- and the
postmaster will be "S"ilent. Notice that there
+ and the
postmaster will be "S"ilent.
+Notice that there
is no ampersand ("&") at the end of the last example.
createuser enables specific users to access
-
Postgres.
destroyuser removes users and
- prevents them from accessing
Postgres. Note that these
- commands only affect users with respect to
Postgres;
+
destroyuser removes users and
+ prevents them from accessing
Postgres.
+Note that these
+ commands only affect users with respect to
they have no effect on users other privileges or status with regards
to the underlying
operating system.
-Usually, you will want to define this variable in the
Postgres superuser's
+Usually, you will want to define this variable in the
.profile
or
.cshrc
Assuming that your site administrator has properly
- started the
postmaster process and authorized you to
+ started the
postmaster process
+and authorized you to
use the database, you (as a user) may begin to start up
applications. As previously mentioned, you should add
/usr/local/pgsql/bin to your shell search path.
terms of preparation.
- If you get the following error message from a
Postgres- command (such as
psql or
createdb):
+ If you get the following error message from a
+ command (such as
psql or
-connectDB() failed: Is the postmaster running at 'localhost' on port '4322'?
+connectDB() failed: Is the postmaster running at 'localhost' on port '5432'?
it is usually because either the
postmaster is not running,
or you are attempting to connect to the wrong server host.
Managing a Database
- Now that
Postgres is up and running we can create
some- databases to experiment with. Here, we describe the
+ Now that
Postgres is up and running we can create
+ some databases to experiment with. Here, we describe the
basic commands for managing a database.
% createdb mydb
-
Postgres allows you to create any number of databases
+
Postgres allows you to create
+any number of databases
at a given site and you automatically become the
- database administrator of the database you just created. Database names must have an alphabetic first
+ database administrator of the database you just created.
+Database names must have an alphabetic first
character and are limited to 16 characters in length.
Not every user has authorization to become a database
- administrator. If
Postgres refuses to create databases
+ administrator. If
Postgres +refuses to create databases
for you, then the site administrator needs to grant you
permission to create databases. Consult your site
administrator if this occurs.
-running the
Postgres terminal monitor program
s (-
monitor or psql) which allows you to interactively
+running the
Postgres terminal monitor program
+
(psql) which allows you to interactively
enter, edit, and execute
SQL commands.
- writing a C program using the LIBPQ subroutine
+ writing a C program using the libpq subroutine
library. This allows you to submit
SQL commands
from C and get answers and status messages back to
your program. This interface is discussed further
- in section ??.
+ in the PostgreSQL Programmer's Guide.
- You might want to start up
psql, to try out the examples in this manual. It can be activated for the mydb
+ You might want to start up
psql,
+to try out the examples in this manual. It can be activated for the mydb
database by typing the command:
% psql mydb
-This prompt indicates that the terminal monitor is listening to you and that you can type
SQL queries into a
+This prompt indicates that the terminal monitor is listening
+to you and that you can type
SQL queries into a
workspace maintained by the terminal monitor.
- The
psql program responds to escape codes that begin
+ The
psql program responds to escape
+ codes that begin
with the backslash character, "\". For example, you
- can get help on the syntax of various
Postgres SQL commands by typing:
+ can get help on the syntax of various
+
Postgres SQL commands by typing:
mydb=> \h
This tells the server to process the query. If you
terminate your query with a semicolon, the backslash-g is not
- necessary.
psql will automatically process semicolon terminated queries.
+ necessary.
psql will automatically
+process semicolon terminated queries.
To read queries from a file, say myFile, instead of
entering them interactively, type:
mydb=> \q
- and
psql will quit and return you to your command
+ and
psql will quit and return
+you to your command
shell. (For more escape codes, type backslash-h at the monitor
prompt.)
White space (i.e., spaces, tabs and newlines) may be
- used freely in
SQL queries. Single-line comments are denoted by
+ used freely in
SQL queries.
+Single-line comments are denoted by
--
. Everything after the dashes up to the end of the
line is ignored. Multiple-line comments, and comments within a line,
are denoted by /* ... */
--- /dev/null
+
+
SQL Syntax
+
+
+
Key Words
+
+
SQL92 defines
key words for the language
+which have specific meaning. Some key words are
+reserved, which indicates that they are
+restricted to appear in only certain contexts. Other key words are
+not restricted, which indicates that in certain contexts they
+have a specific meaning but are not otherwise constrained.
+
+
Postgres implements an extended subset of the
+
SQL92 and
SQL3 languages. Some language
+elements are not as restricted in this implementation as is
+called for in the language standards, in part due
+to the extensibility features of
Postgres.
+
+Information on
SQL92 and
SQL3 key words
+is derived from .
+
+
+
Reserved Key Words
+
+reserved key words which are not allowed
+as identifiers and not allowed in any usage other than as fundamental
+tokens in
SQL statements.
+
Postgres has additional key words
+which have similar restrictions. In particular, these key words
+are not allowed as column or table names, though in some cases
+they are allowed to be column labels (i.e. in AS clauses).
+
+
+Any string can be specified as an identifier if surrounded by
+double quotes (like this!
). Some care is required since
+such an identifier will be case sensitive
+and will retain embedded whitespace.
+
+
+The following are
Postgres+reserved words which are neither
SQL92+nor
SQL3 reserved words. These are allowed
+to be present as column labels, but not as identifiers:
+
+ABORT ANALYZE
+BINARY
+CLUSTER CONSTRAINT COPY
+DO
+EXPLAIN EXTEND
+LISTEN LOAD LOCK
+MOVE
+NEW NONE NOTIFY
+RESET
+SETOF SHOW
+UNLISTEN UNTIL
+VACUUM VERBOSE
+
+
+The following are
Postgres+reserved words which are also
SQL92 +or
SQL3 reserved words, and which
+are allowed to be present as column labels, but not as identifiers:
+
+CROSS CURRENT
+FALSE FOREIGN
+GROUP
+ORDER
+POSITION PRECISION
+TABLE TRANSACTION TRUE
+
+
+The following are
Postgres+reserved words which are also
SQL92 +
+ADD ALL ALTER AND ANY AS ASC
+BEGIN BETWEEN BOTH BY
+CASCADE CAST CHAR CHARACTER CHECK CLOSE COLLATE COLUMN COMMIT
+CONSTRAINT CREATE CURRENT_DATE CURRENT_TIME
+CURRENT_TIMESTAMP CURRENT_USER CURSOR
+DECIMAL DECLARE DEFAULT DELETE DESC DISTINCT DROP
+END EXECUTE EXISTS EXTRACT
+FETCH FLOAT FOR FROM FULL
+GRANT
+HAVING
+IN INNER INSERT INTERVAL INTO IS
+JOIN
+LEADING LEFT LIKE LOCAL
+NAMES NATIONAL NATURAL NCHAR NO NOT NULL NUMERIC
+ON OR OUTER
+PARTIAL PRIMARY PRIVILEGES PROCEDURE PUBLIC
+REFERENCES REVOKE RIGHT ROLLBACK
+SELECT SET SUBSTRING
+TIMESTAMP TO TRAILING TRIM
+UNION UNIQUE UPDATE USER USING
+VALUES VARCHAR VARYING VIEW
+WHERE WITH WORK
+
+
+The following are
SQL92 reserved key words which
+are not
Postgres reserved key words, but which
+if used as function names are always translated into the function
+length:
+
+CHAR_LENGTH CHARACTER_LENGTH
+
+
+The following are
SQL92 or
SQL3 +reserved key words which
+are not
Postgres reserved key words, but
+if used as type names which are always translated into an alternate, native type:
+
+BOOLEAN DOUBLE FLOAT INT INTEGER INTERVAL REAL SMALLINT
+
+
+The following are either
SQL92+or
SQL3 reserved key words
+which are not key words in
Postgres.
+These have no proscribed usage in
Postgres+at the time of writing (v6.4) but may become reserved key words in the
+future:
+
+
+Some of these key words represent functions in
SQL92.
+These functions are defined in
Postgres,
+but the parser does not consider the names to be key words and they are allowed
+in other contexts.
+
+
+ALLOCATE ARE ASSERTION AT AUTHORIZATION AVG
+BIT BIT_LENGTH
+CASCADED CASE CATALOG COALESCE COLLATION
+CONNECT CONNECTION CONSTRAINTS CONTINUE CONVERT CORRESPONDING COUNT
+DATE DEALLOCATE DEC DESCRIBE DESCRIPTOR DIAGNOSTICS DISCONNECT DOMAIN
+ELSE END-EXEC ESCAPE EXCEPT EXCEPTION EXEC EXTERNAL
+FIRST FOUND
+GET GLOBAL GO GOTO
+IDENTITY IMMEDIATE INDICATOR INITIALLY INPUT INTERSECT ISOLATION
+LAST LEVEL LOWER
+MAX MIN MODULE
+NULLIF
+OCTET_LENGTH OPEN OUTPUT OVERLAPS
+PREPARE PRESERVE
+RESTRICT ROWS
+SCHEMA SECTION SESSION SESSION_USER SIZE SOME
+SQL SQLCODE SQLERROR SQLSTATE SUM SYSTEM_USER
+TEMPORARY THEN TRANSLATE TRANSLATION
+UNKNOWN UPPER USAGE
+VALUE
+WHEN WHENEVER WRITE
+
+
+
+
Non-reserved Keywords
+
+non-reserved keywords which have
+a proscribed meaning in the language but which are also allowed
+as identifiers.
+
Postgres has additional keywords
+which allow similar unrestricted usage.
+In particular, these keywords
+are allowed as column or table names.
+
+The following are
Postgres+non-reserved key words which are neither
SQL92+nor
SQL3 non-reserved key words:
+
+AFTER AGGREGATE
+BACKWARD BEFORE
+CACHE CREATEDB CREATEUSER CYCLE
+DATABASE DELIMITERS
+EACH ENCODING
+FORWARD FUNCTION
+HANDLER
+INCREMENT INDEX INHERITS INSENSITIVE INSTEAD ISNULL
+LANCOMPILER LOCATION
+MAXVALUE MINVALUE
+NOCREATEDB NOCREATEUSER NOTHING NOTNULL
+OIDS OPERATOR
+PASSWORD PROCEDURAL
+RECIPE RENAME RETURNS ROW RULE
+SEQUENCE SERIAL START STATEMENT STDIN STDOUT
+TRUSTED
+VALID VERSION
+
+
+The following are
Postgres+non-reserved key words which are
SQL92+or
SQL3 reserved key words:
+
+ABSOLUTE ACTION
+DAY
+HOUR
+INSENSITIVE
+KEY
+LANGUAGE
+MATCH MINUTE MONTH
+NEXT
+OF ONLY OPTION
+PRIOR PRIVILEGES
+READ RELATIVE
+SCROLL SECOND
+TIME TIMEZONE_HOUR TIMEZONE_MINUTE TRIGGER
+YEAR
+ZONE
+
+
+The following are
Postgres+non-reserved key words which are also either
SQL92+or
SQL3 non-reserved key words:
+
+TYPE
+
+
+The following are either
SQL92+or
SQL3 non-reserved key words which are not
+key words of any kind in
Postgres:
+
+ADA
+C CATALOG_NAME CHARACTER_SET_CATALOG CHARACTER_SET_NAME
+CHARACTER_SET_SCHEMA CLASS_ORIGIN COBOL COLLATION_CATALOG
+COLLATION_NAME COLLATION_SCHEMA COLUMN_NAME
+COMMAND_FUNCTION COMMITTED CONDITION_NUMBER
+CONNECTION_NAME CONSTRAINT_CATALOG CONSTRAINT_NAME
+CONSTRAINT_SCHEMA CURSOR_NAME
+DATA DATE_TIME_INTERVAL_CODE DATE_TIME_INTERVAL_PRECISION
+DYNAMIC_FUNCTION
+FORTRAN
+LENGTH
+MESSAGE_LENGTH MESSAGE_OCTET_LENGTH MORE MUMPS
+NAME NULLABLE NUMBER
+PAD PASCAL PLI
+REPEATABLE RETURNED_LENGTH RETURNED_OCTET_LENGTH
+RETURNED_SQLSTATE ROW_COUNT
+SCALE SCHEMA_NAME SERIALIZABLE SERVER_NAME SPACE
+SUBCLASS_ORIGIN
+TABLE_NAME
+UNCOMMITTED UNNAMED
+
+
+
+
+
+
+
+
+
%allfiles;
]>
-
+
&intro;
&environ;
&manage;
+&syntax;
&datatype;
&oper;
&func;
projects / postgresql.git / commitdiff