mirror of
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Add new files from Oliver Elphick.
This commit is contained in:
Thomas G. Lockhart
parent
a9d76d0108
commit
64fbd1fb12
@ -1,43 +1,109 @@
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<Chapter>
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<Title>Commands</Title>
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<!-- allfiles.sgml
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-
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- Complete list of usable sgml source files in this directory.
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-
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- -->
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<Para>
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</Para>
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<!entity intro-ref system "intro-ref.sgml">
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<!entity commands system "commands.sgml">
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&alterTable;
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&alterUser;
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&begin;
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&close;
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&cluster;
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&commit;
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©
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&createAggregate;
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&createDatabase;
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&createFunction;
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&createIndex;
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&createLanguage;
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&createOperator;
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&createRule;
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&createSequence;
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&createTable;
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&dropFunction;
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&select;
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<!-- these will go into the "operators" reference chapter -->
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<!entity all system "all.sgml">
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<!entity any system "any.sgml">
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<!entity between system "between.sgml">
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<!entity in system "in.sgml">
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<!entity like system "like.sgml">
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</Chapter>
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<!-- these will go into the "functions" reference chapter -->
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<!entity avg system "avg.sgml">
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<!entity cast system "cast.sgml">
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||||
<!entity charLength system "char_length.sgml">
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||||
<!entity count system "count.sgml">
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<!entity currentDate system "current_date.sgml">
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||||
<!entity currentTime system "current_time.sgml">
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||||
<!entity currentTimestamp system "current_timestamp.sgml">
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||||
<!entity currentUser system "current_user.sgml">
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||||
<!entity exists system "exists.sgml">
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||||
<!entity extract system "extract.sgml">
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||||
<!entity initcap system "initcap.sgml">
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||||
<!entity lower system "lower.sgml">
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||||
<!entity lpad system "lpad.sgml">
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||||
<!entity max system "max.sgml">
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||||
<!entity min system "min.sgml">
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||||
<!entity position system "position.sgml">
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||||
<!entity rpad system "rpad.sgml">
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||||
<!entity substring system "substring.sgml">
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||||
<!entity sum system "sum.sgml">
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||||
<!entity translate system "translate.sgml">
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<!entity trim system "trim.sgml">
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||||
<!entity upper system "upper.sgml">
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||||
|
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
|
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sgml-shorttag:t
|
||||
sgml-minimize-attributes:nil
|
||||
sgml-always-quote-attributes:t
|
||||
sgml-indent-step:1
|
||||
sgml-indent-data:t
|
||||
sgml-parent-document:nil
|
||||
sgml-default-dtd-file:"../reference.ced"
|
||||
sgml-exposed-tags:nil
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||||
sgml-local-catalogs:"/usr/lib/sgml/catalog"
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||||
sgml-local-ecat-files:nil
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||||
End:
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||||
<!-- these are folded into create_table.sgml
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<!entity check system "check.sgml">
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<!entity constraints system "constraint.sgml">
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<!entity default system "default.sgml">
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||||
<!entity notNull system "not_null.sgml">
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<!entity primaryKey system "primary_key.sgml">
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<!entity unique system "unique.sgml">
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-->
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||||
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<!-- these are folded into select.sgml
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<!entity groupBy system "group_by.sgml">
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<!entity having system "having.sgml">
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<!entity orderBy system "order_by.sgml">
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<!entity union system "union.sgml">
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-->
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<!-- these are in the "commands" reference chapter -->
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<!entity alterTable system "alter_table.sgml">
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<!entity alterUser system "alter_user.sgml">
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<!entity begin system "begin.sgml">
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<!entity close system "close.sgml">
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||||
<!entity cluster system "cluster.sgml">
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||||
<!entity commit system "commit.sgml">
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||||
<!entity copy system "copy.sgml">
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<!entity createAggregate system "create_aggregate.sgml">
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<!entity createDatabase system "create_database.sgml">
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<!entity createFunction system "create_function.sgml">
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<!entity createIndex system "create_index.sgml">
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<!entity createLanguage system "create_language.sgml">
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<!entity createOperator system "create_operator.sgml">
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<!entity createRule system "create_rule.sgml">
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<!entity createSequence system "create_sequence.sgml">
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<!entity createTable system "create_table.sgml">
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<!entity createTrigger system "create_trigger.sgml">
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<!entity createType system "create_type.sgml">
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<!entity createUser system "create_user.sgml">
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<!entity createView system "create_view.sgml">
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<!entity declare system "declare.sgml">
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<!entity delete system "delete.sgml">
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<!entity dropAggregate system "drop_aggregate.sgml">
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||||
<!entity dropDatabase system "drop_database.sgml">
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||||
<!entity dropFunction system "drop_function.sgml">
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||||
<!entity dropIndex system "drop_index.sgml">
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<!entity dropLanguage system "drop_language.sgml">
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||||
<!entity dropOperator system "drop_operator.sgml">
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<!entity dropRule system "drop_rule.sgml">
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<!entity dropSequence system "drop_sequence.sgml">
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||||
<!entity dropTable system "drop_table.sgml">
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<!entity dropTrigger system "drop_trigger.sgml">
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<!entity dropType system "drop_type.sgml">
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<!entity dropUser system "drop_user.sgml">
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<!entity dropView system "drop_view.sgml">
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<!entity explain system "explain.sgml">
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||||
<!entity fetch system "fetch.sgml">
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<!entity grant system "grant.sgml">
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||||
<!entity insert system "insert.sgml">
|
||||
<!entity listen system "listen.sgml">
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||||
<!entity load system "load.sgml">
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||||
<!entity lock system "lock.sgml">
|
||||
<!entity move system "move.sgml">
|
||||
<!entity notify system "notify.sgml">
|
||||
<!entity reset system "reset.sgml">
|
||||
<!entity revoke system "revoke.sgml">
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||||
<!entity rollback system "rollback.sgml">
|
||||
<!entity select system "select.sgml">
|
||||
<!entity set system "set.sgml">
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<!entity show system "show.sgml">
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<!entity update system "update.sgml">
|
||||
<!entity vacuum system "vacuum.sgml">
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|
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247
doc/src/sgml/ref/create_trigger.sgml
Normal file
247
doc/src/sgml/ref/create_trigger.sgml
Normal file
@ -0,0 +1,247 @@
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<REFENTRY ID="SQL-CREATETRIGGER-1">
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<REFMETA>
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<REFENTRYTITLE>
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CREATE TRIGGER
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</REFENTRYTITLE>
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<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
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</REFMETA>
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<REFNAMEDIV>
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<REFNAME>
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CREATE TRIGGER
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</REFNAME>
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<REFPURPOSE>
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CREATE TRIGGER - creates a new trigger.
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</REFPURPOSE>
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<REFSYNOPSISDIV>
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<REFSYNOPSISDIVINFO>
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<DATE>1998-04-15</DATE>
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</REFSYNOPSISDIVINFO>
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<SYNOPSIS>
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CREATE TRIGGER <REPLACEABLE CLASS="PARAMETER">name</REPLACEABLE> { BEFORE | AFTER }
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{ <REPLACEABLE CLASS="PARAMETER">event</REPLACEABLE> [OR ...] }
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ON <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE> FOR EACH { ROW | STATEMENT }
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EXECUTE PROCEDURE <REPLACEABLE CLASS="PARAMETER">funcname</REPLACEABLE> ( <REPLACEABLE CLASS="PARAMETER">arguments</REPLACEABLE> )
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</SYNOPSIS>
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<REFSECT2 ID="R2-SQL-CREATETRIGGER-1">
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<REFSECT2INFO>
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<DATE>1998-04-15</DATE>
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</REFSECT2INFO>
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<TITLE>
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Inputs
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</TITLE>
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<PARA>
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</PARA>
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<VARIABLELIST>
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<VARLISTENTRY>
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<TERM>
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</TERM>
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<LISTITEM>
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||||
<PARA>
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<VARIABLELIST>
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<VARLISTENTRY>
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<TERM>
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<ReturnValue><replaceable class="parameter">name</replaceable></ReturnValue>
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</TERM>
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<LISTITEM>
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<PARA>
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The name of an existing trigger.
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</PARA>
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</LISTITEM>
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</VARLISTENTRY>
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<VARLISTENTRY>
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<TERM>
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<ReturnValue><replaceable class="parameter">table</replaceable></ReturnValue>
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</TERM>
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<LISTITEM>
|
||||
<PARA>
|
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The name of a table.
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</PARA>
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</LISTITEM>
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</VARLISTENTRY>
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<VARLISTENTRY>
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||||
<TERM>
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<ReturnValue><replaceable class="parameter">event</replaceable></ReturnValue>
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</TERM>
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<LISTITEM>
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<PARA>
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One of INSERT, DELETE or UPDATE.
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</PARA>
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</LISTITEM>
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</VARLISTENTRY>
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<VARLISTENTRY>
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<TERM>
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<ReturnValue><replaceable class="parameter">funcname</replaceable></ReturnValue>
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</TERM>
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<LISTITEM>
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<PARA>
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A user-supplied function.
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</PARA>
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</LISTITEM>
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</VARLISTENTRY>
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</variablelist>
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</LISTITEM>
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</VARLISTENTRY>
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</VARIABLELIST>
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</REFSECT2>
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<REFSECT2 ID="R2-SQL-CREATETRIGGER-2">
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<REFSECT2INFO>
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<DATE>1998-04-15</DATE>
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</REFSECT2INFO>
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<TITLE>
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Outputs
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</TITLE>
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<PARA>
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</PARA>
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<VARIABLELIST>
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<VARLISTENTRY>
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||||
<TERM>
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||||
</TERM>
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||||
<LISTITEM>
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||||
<PARA>
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||||
<VARIABLELIST>
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<VARLISTENTRY>
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<TERM>
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<ReturnValue>CREATE</ReturnValue>
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</TERM>
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<LISTITEM>
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<PARA>
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This message is returned if the trigger is successfully created.
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</PARA>
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</LISTITEM>
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</VARLISTENTRY>
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||||
</variablelist>
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||||
</LISTITEM>
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</VARLISTENTRY>
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</VARIABLELIST>
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</REFSECT2>
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</REFSYNOPSISDIV>
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<REFSECT1 ID="R1-SQL-CREATETRIGGER-1">
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<REFSECT1INFO>
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<DATE>1998-04-15</DATE>
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</REFSECT1INFO>
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||||
<TITLE>
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||||
Description
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</TITLE>
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<PARA>
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CREATE TRIGGER will enter a new trigger into the current
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data base. The trigger will be associated with the relation
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<replaceable class="parameter">relname</replaceable> and will execute
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the specified function <replaceable class="parameter">funcname</replaceable>.
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</PARA>
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||||
<PARA>
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||||
Only the relation owner may create a trigger on this relation.
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||||
</PARA>
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||||
<PARA>
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||||
At release 6.3.2, STATEMENT triggers are not implemented.
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</PARA>
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||||
<PARA>
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||||
The trigger can be specified to fire either before the
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operation is attempted on a tuple (before constraints
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are checked and the INSERT, UPDATE or DELETE is attempted) or
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after the operation has been attempted (e.g. after constraints
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||||
are checked and the INSERT, UPDATE or DELETE has completed). If the
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trigger fires before the event, the trigger may
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skip the operation for the current tuple, or change the tuple
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being inserted (for INSERT and UPDATE operations only). If
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the trigger fires after the event, all changes, including the
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last INSERTion, UPDATE or DELETion, are "visible" to the trigger.
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||||
</PARA>
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||||
<PARA>
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||||
Refer to the SPI and trigger programming guides for more
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||||
information.
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||||
</PARA>
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||||
<REFSECT2 ID="R2-SQL-CREATETRIGGER-3">
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<REFSECT2INFO>
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<DATE>1998-04-15</DATE>
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||||
</REFSECT2INFO>
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||||
<TITLE>
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||||
Notes
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</TITLE>
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<PARA>
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CREATE TRIGGER statement is a PostgreSQL language extension.
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</PARA>
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||||
<PARA>
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Refer to the DROP TRIGGER statement for information on how to
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remove triggers.
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||||
</PARA>
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||||
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||||
</REFSECT2>
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||||
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||||
<REFSECT1 ID="R1-SQL-CREATETRIGGER-2">
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<TITLE>
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||||
Usage
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</TITLE>
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||||
<PARA>
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||||
Check if the specified distributor code exists in the distributors
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table before appending or updating a row in the table films:
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</PARA>
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<ProgramListing>
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CREATE TRIGGER if_dist_exists
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BEFORE INSERT OR UPDATE ON films FOR EACH ROW
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EXECUTE PROCEDURE check_primary_key ('did', 'distributors', 'did');
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</ProgramListing>
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||||
<PARA>
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||||
Before cancelling a distributor or updating its code, remove every
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||||
reference to the table films:
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</PARA>
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<ProgramListing>
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CREATE TRIGGER if_film_exists
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BEFORE DELETE OR UPDATE ON distributors FOR EACH ROW
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EXECUTE PROCEDURE check_foreign_key (1, 'CASCADE', 'did', 'films', 'did');
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</ProgramListing>
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||||
</REFSECT1>
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||||
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||||
<REFSECT1 ID="R1-SQL-CREATETRIGGER-3">
|
||||
<TITLE>
|
||||
Compatibility
|
||||
</TITLE>
|
||||
<PARA>
|
||||
</PARA>
|
||||
|
||||
<REFSECT2 ID="R2-SQL-CREATETRIGGER-4">
|
||||
<REFSECT2INFO>
|
||||
<DATE>1998-04-15</DATE>
|
||||
</REFSECT2INFO>
|
||||
<TITLE>
|
||||
SQL92
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||||
</TITLE>
|
||||
<PARA>
|
||||
There is no CREATE TRIGGER statement in SQL92.
|
||||
</PARA>
|
||||
<PARA>
|
||||
The second example above may also be done by using a FOREIGN KEY
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||||
constraint as in:
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</PARA>
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||||
<ProgramListing>
|
||||
CREATE TABLE distributors (
|
||||
did DECIMAL(3),
|
||||
name VARCHAR(40),
|
||||
CONSTRAINT if_film_exists FOREIGN KEY(did) REFERENCES films
|
||||
ON UPDATE CASCADE ON DELETE CASCADE
|
||||
);
|
||||
</ProgramListing>
|
||||
<PARA>
|
||||
However, foreign keys are not yet implemented at version 6.3.2 of
|
||||
PostgreSQL.
|
||||
</PARA>
|
||||
</REFENTRY>
|
||||
|
||||
<!-- Keep this comment at the end of the file
|
||||
Local variables:
|
||||
mode: sgml
|
||||
sgml-omittag:t
|
||||
sgml-shorttag:t
|
||||
sgml-minimize-attributes:nil
|
||||
sgml-always-quote-attributes:t
|
||||
sgml-indent-step:1
|
||||
sgml-indent-data:t
|
||||
sgml-parent-document:nil
|
||||
sgml-default-dtd-file:"../reference.ced"
|
||||
sgml-exposed-tags:nil
|
||||
sgml-local-catalogs:"/usr/lib/sgml/catalog"
|
||||
sgml-local-ecat-files:nil
|
||||
End:
|
||||
-->
|
||||
438
doc/src/sgml/ref/create_type.sgml
Normal file
438
doc/src/sgml/ref/create_type.sgml
Normal file
@ -0,0 +1,438 @@
|
||||
<REFENTRY ID="SQL-CREATETYPE-1">
|
||||
<REFMETA>
|
||||
<REFENTRYTITLE>
|
||||
CREATE TYPE
|
||||
</REFENTRYTITLE>
|
||||
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
|
||||
</REFMETA>
|
||||
<REFNAMEDIV>
|
||||
<REFNAME>
|
||||
CREATE TYPE
|
||||
</REFNAME>
|
||||
<REFPURPOSE>
|
||||
CREATE TYPE - defines a new base data type.
|
||||
</REFPURPOSE>
|
||||
<REFSYNOPSISDIV>
|
||||
<REFSYNOPSISDIVINFO>
|
||||
<DATE>1998-04-15</DATE>
|
||||
</REFSYNOPSISDIVINFO>
|
||||
<SYNOPSIS>
|
||||
CREATE TYPE <replaceable class="parameter">typename</replaceable> (
|
||||
INTERNALLENGTH = (<replaceable class="parameter">internallength</replaceable> | VARIABLE)
|
||||
[, EXTERNALLENGTH = (<replaceable class="parameter">externallength</replaceable> | VARIABLE) ]
|
||||
<comment>
|
||||
Why are parentheses required around the length parameters?
|
||||
</comment>
|
||||
, INPUT = <replaceable class="parameter">input_function</replaceable>
|
||||
, OUTPUT = <replaceable class="parameter">output_function</replaceable>
|
||||
[, ELEMENT = <replaceable class="parameter">element</replaceable>]
|
||||
[, DELIMITER = <replaceable class="parameter">delimiter</replaceable>]
|
||||
[, DEFAULT = "<replaceable class="parameter">default</replaceable>" ]
|
||||
[, SEND = <replaceable class="parameter">send_function</replaceable> ]
|
||||
[, RECEIVE = <replaceable class="parameter">receive_function</replaceable> ]
|
||||
[, PASSEDBYVALUE])
|
||||
</SYNOPSIS>
|
||||
|
||||
<REFSECT2 ID="R2-SQL-CREATETYPE-1">
|
||||
<REFSECT2INFO>
|
||||
<DATE>1998-04-15</DATE>
|
||||
</REFSECT2INFO>
|
||||
<TITLE>
|
||||
Inputs
|
||||
</TITLE>
|
||||
<PARA>
|
||||
</PARA>
|
||||
<VARIABLELIST>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
<VARIABLELIST>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">typename</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The name of a type to be created.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">internallength</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
A literal value, which specifies the internal length of
|
||||
the new type.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">externallength</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
A literal value, which specifies the external length of
|
||||
the new type.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">input_function</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The name of a function, created by CREATE FUNCTION, which
|
||||
converts data from its external form to the type's
|
||||
internal form.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">output_function</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The name of a function, created by CREATE FUNCTION, which
|
||||
converts data from its internal form to a form suitable
|
||||
for display.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">element</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The type being created is an array; this specifies
|
||||
the type of the array elements.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">delimiter</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The delimiter character for the array.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">default</replaceable
|
||||
></ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The default text to be displayed to indicate "data
|
||||
not present"
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">send_function</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The name of a function, created by CREATE FUNCTION, which
|
||||
converts data of this type into a form suitable for
|
||||
transmission to another machine.
|
||||
<comment>Is this right?</comment>
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>
|
||||
<replaceable class="parameter">receive_function</replaceable>
|
||||
</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
The name of a function, created by CREATE FUNCTION, which
|
||||
converts data of this type from a form suitable for
|
||||
transmission from another machine to internal form.
|
||||
<comment>Is this right?</comment>
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
</variablelist>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
</VARIABLELIST>
|
||||
</REFSECT2>
|
||||
|
||||
<REFSECT2 ID="R2-SQL-CREATETYPE-2">
|
||||
<REFSECT2INFO>
|
||||
<DATE>1998-04-15</DATE>
|
||||
</REFSECT2INFO>
|
||||
<TITLE>
|
||||
Outputs
|
||||
</TITLE>
|
||||
<PARA>
|
||||
</PARA>
|
||||
<VARIABLELIST>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
<VARIABLELIST>
|
||||
<VARLISTENTRY>
|
||||
<TERM>
|
||||
<ReturnValue>CREATE</ReturnValue>
|
||||
</TERM>
|
||||
<LISTITEM>
|
||||
<PARA>
|
||||
Message returned if the type is successfully created.
|
||||
</PARA>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
</variablelist>
|
||||
</LISTITEM>
|
||||
</VARLISTENTRY>
|
||||
</VARIABLELIST>
|
||||
|
||||
</REFSECT2>
|
||||
</REFSYNOPSISDIV>
|
||||
|
||||
<REFSECT1 ID="R1-SQL-CREATETYPE-1">
|
||||
<REFSECT1INFO>
|
||||
<DATE>1998-04-15</DATE>
|
||||
</REFSECT1INFO>
|
||||
<TITLE>
|
||||
Description
|
||||
</TITLE>
|
||||
<PARA>
|
||||
CREATE TYPE allows the user to register a new user data
|
||||
type with Postgres for use in the current data base. The
|
||||
user who defines a type becomes its owner.
|
||||
<replaceable class="parameter">Typename</replaceable> is
|
||||
the name of the new type and must be unique within the
|
||||
types defined for this database.
|
||||
</para>
|
||||
<PARA>
|
||||
CREATE TYPE requires the registration of two functions
|
||||
(using create function) before defining the type. The
|
||||
representation of a new base type is determined by
|
||||
<replaceable class="parameter">input_function</replaceable>, which
|
||||
converts the type's external representation to an internal
|
||||
representation usable by the
|
||||
operators and functions defined for the type. Naturally,
|
||||
<replaceable class="parameter">output_function</replaceable>
|
||||
performs the reverse transformation. Both
|
||||
the input and output functions must be declared to take
|
||||
one or two arguments of type "<literal>opaque</literal>".
|
||||
</para>
|
||||
<PARA>
|
||||
New base data types can be fixed length, in which case
|
||||
<replaceable class="parameter">internallength</replaceable> is a
|
||||
positive integer, or variable length,
|
||||
in which case Postgres assumes that the new type has the
|
||||
same format
|
||||
as the Postgres-supplied data type, "<literal>text</literal>".
|
||||
To indicate that a type is variable-length, set
|
||||
<replaceable class="parameter">internallength</replaceable>
|
||||
to VARIABLE.
|
||||
The external representation is similarly specified using the
|
||||
<replaceable class="parameter">externallength</replaceable>
|
||||
keyword.
|
||||
</para>
|
||||
<PARA>
|
||||
To indicate that a type is an array and to indicate that a
|
||||
type has array elements, indicate the type of the array
|
||||
element using the element keyword. For example, to define
|
||||
an array of 4 byte integers ("int4"), specify
|
||||
<programlisting>ELEMENT = int4</programlisting>
|
||||
</para>
|
||||
<PARA>
|
||||
To indicate the delimiter to be used on arrays of this
|
||||
type, <replaceable class="parameter">delimiter</replaceable>
|
||||
can be
|
||||
set to a specific character. The default delimiter is the comma
|
||||
("<literal>,</literal>").
|
||||
</para>
|
||||
<PARA>
|
||||
A default value is optionally available in case a user
|
||||
wants some specific bit pattern to mean "data not present."
|
||||
Specify the default with the DEFAULT keyword.
|
||||
<comment>How does the user specify that bit pattern and associate
|
||||
it with the fact that the data is not present></comment>
|
||||
</para>
|
||||
<PARA>
|
||||
The optional functions
|
||||
<replaceable class="parameter">send_function</replaceable> and
|
||||
<replaceable class="parameter">receive_function</replaceable>
|
||||
are used when the application program requesting Postgres
|
||||
services resides on a different machine. In this case,
|
||||
the machine on which Postgres runs may use a format for the data
|
||||
type different from that used on the remote machine.
|
||||
In this case it is appropriate to convert data items to a
|
||||
standard form when sending from the server to the client
|
||||
and converting from the standard format to the machine
|
||||
specific format when the server receives the data from the
|
||||
client. If these functions are not specified, then it is
|
||||
assumed that the internal format of the type is acceptable
|
||||
on all relevant machine architectures. For example, single
|
||||
characters do not have to be converted if passed from
|
||||
a Sun-4 to a DECstation, but many other types do.
|
||||
</para>
|
||||
<PARA>
|
||||
The optional flag, PASSEDBYVALUE, indicates that operators
|
||||
and functions which use this data type should be passed an
|
||||
argument by value rather than by reference. Note that you
|
||||
may not pass by value types whose internal representation is
|
||||
more than four bytes.
|
||||
</para>
|
||||
<PARA>
|
||||
For new base types, a user can define operators, functions
|
||||
and aggregates using the appropriate facilities described
|
||||
in this section.
|
||||
</para>
|
||||
<refsect2>
|
||||
<title>Array Types</title>
|
||||
<para>
|
||||
Two generalized built-in functions, array_in and
|
||||
array_out, exist for quick creation of variable-length
|
||||
array types. These functions operate on arrays of any
|
||||
existing Postgres type.</para>
|
||||
</refsect2>
|
||||
|
||||
<refsect2>
|
||||
<title>Large Object Types</title>
|
||||
<para>
|
||||
A "regular" Postgres type can only be 8192 bytes in
|
||||
length. If you need a larger type you must create a Large
|
||||
Object type. The interface for these types is discussed
|
||||
at length in
|
||||
<comment>This section reference needs replacing</comment>
|
||||
Section 7, the large object interface. The
|
||||
length of all large object types is always VARIABLE.
|
||||
</refsect2>
|
||||
</refsect1>
|
||||
<refsect1>
|
||||
<title>Examples</title>
|
||||
<para>
|
||||
This command creates the box data type and then uses the
|
||||
type in a class definition:
|
||||
</para>
|
||||
<programlisting>
|
||||
CREATE TYPE box (INTERNALLENGTH = 8,
|
||||
INPUT = my_procedure_1, OUTPUT = my_procedure_2)
|
||||
|
||||
CREATE TABLE myboxes (id INT4, description box)
|
||||
</programlisting>
|
||||
<para>
|
||||
This command creates a variable length array type with
|
||||
integer elements.
|
||||
</para>
|
||||
<programlisting>
|
||||
CREATE TYPE int4array
|
||||
(INPUT = array_in, OUTPUT = array_out,
|
||||
INTERNALLENGTH = VARIABLE, ELEMENT = int4)
|
||||
|
||||
CREATE TABLE myarrays (id int4, numbers int4array)
|
||||
</programlisting>
|
||||
<para>
|
||||
This command creates a large object type and uses it in
|
||||
a class definition.
|
||||
</para>
|
||||
<programlisting>
|
||||
CREATE TYPE bigobj
|
||||
(INPUT = lo_filein, OUTPUT = lo_fileout,
|
||||
INTERNALLENGTH = VARIABLE)
|
||||
|
||||
CREATE TABLE big_objs (id int4, obj bigobj)
|
||||
</programlisting>
|
||||
<refsect2>
|
||||
<title>Restrictions</title>
|
||||
<para>
|
||||
Type names cannot begin with the underscore character
|
||||
("_") and can only be 15 characters long. This is because
|
||||
Postgres silently creates an array type for each base type
|
||||
with a name consisting of the base type's name prepended
|
||||
with an underscore.
|
||||
</para>
|
||||
</refsect2>
|
||||
<REFSECT2 ID="R2-SQL-CREATETYPE-3">
|
||||
<REFSECT2INFO>
|
||||
<DATE>1998-04-15</DATE>
|
||||
</REFSECT2INFO>
|
||||
<TITLE>
|
||||
Notes
|
||||
</TITLE>
|
||||
<PARA>
|
||||
Refer to DROP TYPE statement to drop types.
|
||||
</PARA>
|
||||
<PARA>
|
||||
See also CREATE FUNCTION, CREATE OPERATOR and large_objects.</para>
|
||||
</REFSECT2>
|
||||
</refsect1>
|
||||
|
||||
|
||||
<REFSECT1 ID="R1-SQL-CREATETYPE-3">
|
||||
<TITLE>
|
||||
Compatibility
|
||||
</TITLE>
|
||||
<PARA>
|
||||
CREATE TYPE statement is a PostgreSQL language extension.
|
||||
</PARA>
|
||||
|
||||
<REFSECT2 ID="R2-SQL-CREATETYPE-4">
|
||||
<REFSECT2INFO>
|
||||
<DATE>1998-04-15</DATE>
|
||||
</REFSECT2INFO>
|
||||
<TITLE>
|
||||
SQL3
|
||||
</TITLE>
|
||||
<PARA>
|
||||
CREATE TYPE is a SQL3 statement.
|
||||
</PARA>
|
||||
|
||||
</REFSECT2>
|
||||
</REFENTRY>
|
||||
|
||||
|
||||
<!-- Keep this comment at the end of the file
|
||||
Local variables:
|
||||
mode: sgml
|
||||
sgml-omittag:t
|
||||
sgml-shorttag:t
|
||||
sgml-minimize-attributes:nil
|
||||
sgml-always-quote-attributes:t
|
||||
sgml-indent-step:1
|
||||
sgml-indent-data:t
|
||||
sgml-parent-document:nil
|
||||
sgml-default-dtd-file:"../reference.ced"
|
||||
sgml-exposed-tags:nil
|
||||
sgml-local-catalogs:"/usr/lib/sgml/catalog"
|
||||
sgml-local-ecat-files:nil
|
||||
End:
|
||||
-->
|
||||
Loading…
Reference in New Issue
Block a user