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diff --git a/doc/src/sgml/man7/BEGIN.7 b/doc/src/sgml/man7/BEGIN.7 new file mode 100644 index 0000000..1ebd37f --- /dev/null +++ b/doc/src/sgml/man7/BEGIN.7 @@ -0,0 +1,128 @@ +'\" t +.\" Title: BEGIN +.\" Author: The PostgreSQL Global Development Group +.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/> +.\" Date: 2021 +.\" Manual: PostgreSQL 13.4 Documentation +.\" Source: PostgreSQL 13.4 +.\" Language: English +.\" +.TH "BEGIN" "7" "2021" "PostgreSQL 13.4" "PostgreSQL 13.4 Documentation" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +BEGIN \- start a transaction block +.SH "SYNOPSIS" +.sp +.nf +BEGIN [ WORK | TRANSACTION ] [ \fItransaction_mode\fR [, \&.\&.\&.] ] + +where \fItransaction_mode\fR is one of: + + ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED } + READ WRITE | READ ONLY + [ NOT ] DEFERRABLE +.fi +.SH "DESCRIPTION" +.PP +\fBBEGIN\fR +initiates a transaction block, that is, all statements after a +\fBBEGIN\fR +command will be executed in a single transaction until an explicit +\fBCOMMIT\fR(7) +or +\fBROLLBACK\fR(7) +is given\&. By default (without +\fBBEGIN\fR), +PostgreSQL +executes transactions in +\(lqautocommit\(rq +mode, that is, each statement is executed in its own transaction and a commit is implicitly performed at the end of the statement (if execution was successful, otherwise a rollback is done)\&. +.PP +Statements are executed more quickly in a transaction block, because transaction start/commit requires significant CPU and disk activity\&. Execution of multiple statements inside a transaction is also useful to ensure consistency when making several related changes: other sessions will be unable to see the intermediate states wherein not all the related updates have been done\&. +.PP +If the isolation level, read/write mode, or deferrable mode is specified, the new transaction has those characteristics, as if +SET TRANSACTION (\fBSET_TRANSACTION\fR(7)) +was executed\&. +.SH "PARAMETERS" +.PP +WORK +.br +TRANSACTION +.RS 4 +Optional key words\&. They have no effect\&. +.RE +.PP +Refer to +SET TRANSACTION (\fBSET_TRANSACTION\fR(7)) +for information on the meaning of the other parameters to this statement\&. +.SH "NOTES" +.PP +START TRANSACTION (\fBSTART_TRANSACTION\fR(7)) +has the same functionality as +\fBBEGIN\fR\&. +.PP +Use +\fBCOMMIT\fR(7) +or +\fBROLLBACK\fR(7) +to terminate a transaction block\&. +.PP +Issuing +\fBBEGIN\fR +when already inside a transaction block will provoke a warning message\&. The state of the transaction is not affected\&. To nest transactions within a transaction block, use savepoints (see +\fBSAVEPOINT\fR(7))\&. +.PP +For reasons of backwards compatibility, the commas between successive +\fItransaction_modes\fR +can be omitted\&. +.SH "EXAMPLES" +.PP +To begin a transaction block: +.sp +.if n \{\ +.RS 4 +.\} +.nf +BEGIN; +.fi +.if n \{\ +.RE +.\} +.SH "COMPATIBILITY" +.PP +\fBBEGIN\fR +is a +PostgreSQL +language extension\&. It is equivalent to the SQL\-standard command +START TRANSACTION (\fBSTART_TRANSACTION\fR(7)), whose reference page contains additional compatibility information\&. +.PP +The +DEFERRABLE +\fItransaction_mode\fR +is a +PostgreSQL +language extension\&. +.PP +Incidentally, the +BEGIN +key word is used for a different purpose in embedded SQL\&. You are advised to be careful about the transaction semantics when porting database applications\&. +.SH "SEE ALSO" +\fBCOMMIT\fR(7), \fBROLLBACK\fR(7), START TRANSACTION (\fBSTART_TRANSACTION\fR(7)), \fBSAVEPOINT\fR(7) |