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Minor updates for release.

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Split reference pages for CREATE TABLE AS and SELECT INTO to allow psgml
 (the emacs parser) to handle parsing.
This commit is contained in:
Thomas G. Lockhart
1999-06-14 07:37:05 +00:00
parent 5e84d58e70
commit 1ac838edba
19 changed files with 2999 additions and 2821 deletions
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247
doc/src/sgml/ref/begin.sgml
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@@ -1,180 +1,201 @@
<REFENTRY ID="SQL-BEGINWORK">
<REFMETA>
<REFENTRYTITLE>
BEGIN WORK
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
BEGIN WORK
</REFNAME>
<REFPURPOSE>
<refentry id="SQL-BEGINWORK">
<refmeta>
<refentrytitle id="SQL-BEGINWORK-TITLE">
BEGIN
</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>
BEGIN
</refname>
<refpurpose>
Begins a transaction in chained mode
</REFPURPOSE>
</refpurpose>
</refnamediv>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-09-08</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
<refsynopsisdiv>
<refsynopsisdivinfo>
<date>1999-06-11</date>
</refsynopsisdivinfo>
<synopsis>
BEGIN [ WORK | TRANSACTION ]
</SYNOPSIS>
</synopsis>
<REFSECT2 ID="R2-SQL-BEGINWORK-1">
<REFSECT2INFO>
<DATE>1998-09-08</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-BEGINWORK-1">
<refsect2info>
<date>1999-06-11</date>
</refsect2info>
<title>
Inputs
</TITLE>
<PARA>
</title>
<para>
None
</para>
</REFSECT2>
</refsect2>
<REFSECT2 ID="R2-SQL-BEGINWORK-2">
<REFSECT2INFO>
<DATE>1998-09-08</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-BEGINWORK-2">
<refsect2info>
<date>1999-06-11</date>
</refsect2info>
<title>
Outputs
</TITLE>
<PARA>
</title>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<returnvalue>BEGIN</returnvalue>
</TERM>
<LISTITEM>
<PARA>
This signifies that a new transaction has been started.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<returnvalue>NOTICE: BeginTransactionBlock and not in default state</returnvalue>
</TERM>
<LISTITEM>
<PARA>
<para>
<variablelist>
<varlistentry>
<term>
<returnvalue>BEGIN</returnvalue>
</term>
<listitem>
<para>
This signifies that a new transaction has been started.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<returnvalue>NOTICE: BeginTransactionBlock and not in default state</returnvalue>
</term>
<listitem>
<para>
This indicates that a transaction was already in progress.
The current transaction is not affected.
</para>
</listitem>
</varlistentry>
</VARIABLELIST>
</variablelist>
</para>
</REFSECT2>
</REFSYNOPSISDIV>
</refsect2>
</refsynopsisdiv>
<REFSECT1 ID="R1-SQL-BEGINWORK-1">
<REFSECT1INFO>
<DATE>1998-09-08</DATE>
</REFSECT1INFO>
<TITLE>
<refsect1 id="R1-SQL-BEGINWORK-1">
<refsect1info>
<date>1999-06-11</date>
</refsect1info>
<title>
Description
</TITLE>
</title>
<para>
By default, <productname>Postgres</productname> executes transactions
in unchained mode (also known as autocommit feature in other DBMSes).
in <firstterm>unchained mode</firstterm>
(also known as <quote>autocommit</quote> in other database
systems).
In other words, each user statement is executed in its own transaction
and commit is implicit (if execution was successfull).
and a commit is implicitly performed at the end of the statement
(if execution was successful, otherwise a rollback is done).
<command>BEGIN</command> initiates a user transaction in chained mode,
i.e. all user statements after <command>BEGIN</command> command will
be executed in single transaction untill explicit COMMIT, ROLLBACK
be executed in a single transaction until an explicit COMMIT, ROLLBACK
or execution abort. Statements in chained mode are executed much faster,
because of transaction start/commit requires significant CPU and disk
activity. This mode is also required for consistency when changing
one of related tables.
because transaction start/commit requires significant CPU and disk
activity. Execution of multiple statements inside a transaction
is also required for consistency when changing several
related tables.
</para>
<para>
Default transaction isolation level in <productname>Postgres</productname>
is READ COMMITTED one, when queries inside transaction see only changes
The default transaction isolation level in
<productname>Postgres</productname>
is READ COMMITTED, where queries inside the transaction see only changes
committed before query execution. So, you have to use
<command>SET TRANSACTION ISOLATION LEVEL SERIALIZABLE</command>
command just after BEGIN if you need in better transaction isolation.
In SERIALIZABLE mode queries will see only changes committed before entire
transaction began (actually, before execution of first DML statement
in serializable transaction).
just after BEGIN if you need more rigorous transaction isolation.
In SERIALIZABLE mode queries will see only changes committed before
the entire
transaction began (actually, before execution of the first DML statement
in a serializable transaction).
</para>
<para>
If the transaction is committed, <productname>Postgres</productname>
will ensure either that all updates are done or else that none of
them are done. Transactions have the standard ACID
them are done. Transactions have the standard <acronym>ACID</acronym>
(atomic, consistent, isolatable, and durable) property.
</para>
<REFSECT2 ID="R2-SQL-BEGINWORK-3">
<REFSECT2INFO>
<DATE>1998-09-08</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-BEGINWORK-3">
<refsect2info>
<date>1999-06-11</date>
</refsect2info>
<title>
Notes
</TITLE>
<PARA>
</title>
<para>
The keyword TRANSACTION is just a cosmetic alternative to WORK.
Neither keyword need be specified.
</PARA>
</para>
<PARA>
<para>
Refer to the <command>LOCK</command> statement for further information
about locking tables inside a transaction.
</PARA>
</para>
<PARA>
Use <command>COMMIT</command> or <command>ROLLBACK</command>
<para>
Use <xref linkend="SQL-COMMIT-TITLE" endterm="SQL-COMMIT-TITLE">
or
<xref linkend="SQL-ROLLBACK-TITLE" endterm="SQL-ROLLBACK-TITLE">
to terminate a transaction.
</PARA>
</REFSECT2>
</para>
</refsect2>
</refsect1>
<REFSECT1 ID="R1-SQL-BEGINWORK-2">
<TITLE>
Usage
</TITLE>
<PARA>To begin a user transaction:
<ProgramListing>
<refsect1 id="R1-SQL-BEGINWORK-2">
<title>
Usage
</title>
<para>
To begin a user transaction:
<programlisting>
BEGIN WORK;
</ProgramListing>
</programlisting>
</para>
</REFSECT1>
</refsect1>
<REFSECT1 ID="R1-SQL-BEGINWORK-3">
<TITLE>
<refsect1 id="R1-SQL-BEGINWORK-3">
<title>
Compatibility
</TITLE>
<PARA>
</title>
<para>
<command>BEGIN</command>
is a <productname>Postgres</productname> language extension.
</para>
<REFSECT2 ID="R2-SQL-BEGINWORK-4">
<REFSECT2INFO>
<DATE>1998-09-08</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-BEGINWORK-4">
<refsect2info>
<date>1999-06-11</date>
</refsect2info>
<title>
SQL92
</TITLE>
<PARA>
</title>
<para>
There is no explicit BEGIN WORK command in <acronym>SQL92</acronym>;
transaction initiation is always implicit and it terminates either
with a COMMIT or with a ROLLBACK statement.
</PARA>
<PARA>
<acronym>SQL92</acronym> also requires SERIALIZABLE to be default
<note>
<para>
Many relational database systems offer an autocommit feature as a
convenience.
</para>
</note>
</para>
<para>
<acronym>SQL92</acronym> also requires SERIALIZABLE to be the default
transaction isolation level.
</PARA>
</para>
</refsect2>
</refsect1>
</REFENTRY>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-omittag:nil
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t