mirror of https://github.com/postgres/postgres
Add ALTER SEQUENCE to modify min/max/increment/cache/cycle values Also updated create sequence docs to mention NO MINVALUE, & NO MAXVALUE. New Files: doc/src/sgml/ref/alter_sequence.sgml src/test/regress/expected/sequence.out src/test/regress/sql/sequence.sql ALTER SEQUENCE is NOT transactional. It behaves similarly to setval(). It matches the proposed SQL200N spec, as well as Oracle in most ways -- Oracle lacks RESTART WITH for some strange reason. -- Rod Taylor <rbt@rbt.ca>WIN32_DEV
Bruce Momjian
23 years ago
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<!-- |
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$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_sequence.sgml,v 1.1 2003/03/20 07:02:07 momjian Exp $ |
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PostgreSQL documentation |
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--> |
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|
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<refentry id="SQL-ALTERSEQUENCE"> |
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<refmeta> |
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<refentrytitle id="SQL-ALTERSEQUENCE-TITLE">ALTER SEQUENCE</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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ALTER SEQUENCE |
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</refname> |
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<refpurpose> |
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alter the definition of a sequence generator |
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</refpurpose> |
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</refnamediv> |
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<refsynopsisdiv> |
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<refsynopsisdivinfo> |
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<date>1999-07-20</date> |
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</refsynopsisdivinfo> |
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<synopsis> |
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ALTER SEQUENCE <replaceable class="parameter">seqname</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ] |
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[ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ] |
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[ RESTART [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ] |
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</synopsis> |
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|
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<refsect2 id="R2-SQL-ALTERSEQUENCE-1"> |
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<refsect2info> |
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<date>1998-09-11</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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|
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<variablelist> |
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<varlistentry> |
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<term><replaceable class="parameter">seqname</replaceable></term> |
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<listitem> |
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<para> |
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The name (optionally schema-qualified) of a sequence to be altered. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term><replaceable class="parameter">increment</replaceable></term> |
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<listitem> |
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<para> |
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The |
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<option>INCREMENT BY <replaceable class="parameter">increment</replaceable></option> |
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clause is optional. A positive value will make an |
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ascending sequence, a negative one a descending sequence. |
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If unspecified, the old increment value will be maintained. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term><replaceable class="parameter">minvalue</replaceable></term> |
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<term>NO MINVALUE</term> |
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<listitem> |
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<para> |
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The optional clause <option>MINVALUE |
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<replaceable class="parameter">minvalue</replaceable></option> |
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determines the minimum value |
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a sequence can generate. If <option>NO MINVALUE</option> is specified, |
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the defaults of 1 and -2^63-1 for ascending and descending sequences, respectively, will be used. If neither option is specified, the current minimum |
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value will be maintained. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term><replaceable class="parameter">maxvalue</replaceable></term> |
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<term>NO MAXVALUE</term> |
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<listitem> |
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<para> |
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The optional clause <option>MAXVALUE |
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<replaceable class="parameter">maxvalue</replaceable></option> |
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determines the maximum value for the sequence. If |
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<option>NO MAXVALUE</option> is specified, the defaults are 2^63-1 and -1 for |
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ascending and descending sequences, respectively, will be used. If |
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neither option is specified, the current maximum value will be |
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maintained. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term><replaceable class="parameter">start</replaceable></term> |
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<listitem> |
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<para> |
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The optional <option>RESTART WITH |
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<replaceable class="parameter">start</replaceable> |
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clause</option> enables the sequence to re-begin anywhere. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term><replaceable class="parameter">cache</replaceable></term> |
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<listitem> |
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<para> |
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The <option>CACHE <replaceable class="parameter">cache</replaceable></option> option |
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enables sequence numbers to be preallocated |
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and stored in memory for faster access. The minimum |
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value is 1 (only one value can be generated at a time, i.e., no cache). |
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If unspecified, the old cache value will be maintained. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term>CYCLE</term> |
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<listitem> |
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<para> |
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The optional <option>CYCLE</option> keyword may be used to enable |
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the sequence to wrap around when the |
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<replaceable class="parameter">maxvalue</replaceable> or |
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<replaceable class="parameter">minvalue</replaceable> has been |
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reached by |
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an ascending or descending sequence respectively. If the limit is |
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reached, the next number generated will be the |
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<replaceable class="parameter">minvalue</replaceable> or |
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<replaceable class="parameter">maxvalue</replaceable>, |
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respectively. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term>NO CYCLE</term> |
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<listitem> |
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<para> |
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If the optional <option>NO CYCLE</option> keyword is specified, any |
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calls to <function>nextval</function> after the sequence has reached |
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its maximum value will return an error. If neither |
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<option>CYCLE</option> or <option>NO CYCLE</option> are specified, |
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the old cycle behaviour will be maintained. |
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</para> |
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</listitem> |
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</varlistentry> |
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</variablelist> |
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</para> |
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</refsect2> |
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|
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<refsect2 id="R2-SQL-ALTERSEQUENCE-2"> |
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<refsect2info> |
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<date>1998-09-11</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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|
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<variablelist> |
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<varlistentry> |
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<term><computeroutput> |
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ALTER SEQUENCE |
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</computeroutput></term> |
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<listitem> |
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<para> |
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Message returned if the command is successful. |
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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><computeroutput> |
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ERROR: AlterSequence: MINVALUE (<replaceable class="parameter">start</replaceable>) can't be >= MAXVALUE (<replaceable class="parameter">max</replaceable>) |
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</computeroutput></term> |
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<listitem> |
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<para> |
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If the specified starting value is out of range. |
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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><computeroutput> |
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ERROR: AlterSequence: START value (<replaceable class="parameter">start</replaceable>) can't be < MINVALUE (<replaceable class="parameter">min</replaceable>) |
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</computeroutput></term> |
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<listitem> |
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<para> |
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If the specified starting value is out of range. |
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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><computeroutput> |
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ERROR: AlterSequence: MINVALUE (<replaceable class="parameter">min</replaceable>) can't be >= MAXVALUE (<replaceable class="parameter">max</replaceable>) |
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</computeroutput></term> |
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<listitem> |
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<para> |
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If the minimum and maximum values are inconsistent. |
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</para> |
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</listitem> |
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</varlistentry> |
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</variablelist> |
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</para> |
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</refsect2> |
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</refsynopsisdiv> |
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|
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<refsect1 id="R1-SQL-ALTERSEQUENCE-1"> |
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<title> |
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Description |
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</title> |
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|
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<para> |
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See <xref linkend="SQL-CREATESEQUENCE"> for limitations, and uses |
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of sequences. |
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</para> |
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</refsect1> |
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|
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<refsect1 id="R1-SQL-ALTERSEQUENCE-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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Restart a sequence called <literal>serial</literal>, at 105: |
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</para> |
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<programlisting> |
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ALTER SEQUENCE serial RESTART WITH 105; |
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</programlisting> |
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</refsect1> |
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|
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<refsect1 id="R1-SQL-ALTERSEQUENCE-5"> |
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<title> |
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Notes |
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</title> |
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<para> |
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To avoid blocking of concurrent transactions that obtain numbers from the same |
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sequence, a nextval operation is never rolled back; that is, once a value has |
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been fetched it is considered used, even if the transaction that did the nextval |
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later aborts. This means that aborted transactions may leave unused "holes" in |
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the sequence of assigned values. setval operations are never rolled back, either. |
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</para> |
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</refsect1> |
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|
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|
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<refsect1 id="R1-SQL-ALTERSEQUENCE-3"> |
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<title> |
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Compatibility |
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</title> |
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|
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<refsect2 id="R2-SQL-ALTERSEQUENCE-4"> |
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<refsect2info> |
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<date>2003-03-02</date> |
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</refsect2info> |
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<title> |
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SQL99 |
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</title> |
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|
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<para> |
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<command>ALTER SEQUENCE</command> is a <productname>PostgreSQL</productname> |
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language extension. |
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There is no <command>ALTER SEQUENCE</command> statement |
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in <acronym>SQL99</acronym>. |
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</para> |
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</refsect2> |
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</refsect1> |
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</refentry> |
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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:nil |
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sgml-shorttag:t |
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sgml-minimize-attributes:nil |
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sgml-always-quote-attributes:t |
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sgml-indent-step:1 |
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sgml-indent-data:t |
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sgml-parent-document:nil |
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sgml-default-dtd-file:"../reference.ced" |
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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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--> |
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@ -0,0 +1,73 @@ |
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--- |
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--- test creation of SERIAL column |
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--- |
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|
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CREATE TABLE serialTest (f1 text, f2 serial); |
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NOTICE: CREATE TABLE will create implicit sequence 'serialtest_f2_seq' for SERIAL column 'serialtest.f2' |
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|
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INSERT INTO serialTest VALUES ('foo'); |
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INSERT INTO serialTest VALUES ('bar'); |
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INSERT INTO serialTest VALUES ('force', 100); |
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INSERT INTO serialTest VALUES ('wrong', NULL); |
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ERROR: ExecInsert: Fail to add null value in not null attribute f2 |
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|
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SELECT * FROM serialTest; |
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f1 | f2 |
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-------+----- |
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foo | 1 |
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bar | 2 |
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force | 100 |
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(3 rows) |
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|
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CREATE SEQUENCE sequence_test; |
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BEGIN; |
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SELECT nextval('sequence_test'); |
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nextval |
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--------- |
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1 |
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(1 row) |
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|
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DROP SEQUENCE sequence_test; |
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END; |
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-- renaming sequences |
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CREATE SEQUENCE foo_seq; |
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ALTER TABLE foo_seq RENAME TO foo_seq_new; |
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SELECT * FROM foo_seq_new; |
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sequence_name | last_value | increment_by | max_value | min_value | cache_value | log_cnt | is_cycled | is_called |
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---------------+------------+--------------+---------------------+-----------+-------------+---------+-----------+----------- |
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foo_seq | 1 | 1 | 9223372036854775807 | 1 | 1 | 1 | f | f |
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(1 row) |
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|
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DROP SEQUENCE foo_seq_new; |
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-- |
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-- Alter sequence |
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-- |
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CREATE SEQUENCE sequence_test2 START WITH 32; |
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SELECT nextval('sequence_test2'); |
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nextval |
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--------- |
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32 |
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(1 row) |
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|
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ALTER SEQUENCE sequence_test2 RESTART WITH 16 |
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INCREMENT BY 4 MAXVALUE 22 MINVALUE 5 CYCLE; |
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SELECT nextval('sequence_test2'); |
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nextval |
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--------- |
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16 |
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(1 row) |
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|
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SELECT nextval('sequence_test2'); |
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nextval |
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--------- |
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20 |
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(1 row) |
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SELECT nextval('sequence_test2'); |
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nextval |
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--------- |
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5 |
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(1 row) |
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|
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@ -0,0 +1,39 @@ |
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--- |
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--- test creation of SERIAL column |
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--- |
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CREATE TABLE serialTest (f1 text, f2 serial); |
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INSERT INTO serialTest VALUES ('foo'); |
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INSERT INTO serialTest VALUES ('bar'); |
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INSERT INTO serialTest VALUES ('force', 100); |
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INSERT INTO serialTest VALUES ('wrong', NULL); |
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SELECT * FROM serialTest; |
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|
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CREATE SEQUENCE sequence_test; |
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BEGIN; |
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SELECT nextval('sequence_test'); |
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DROP SEQUENCE sequence_test; |
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END; |
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|
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-- renaming sequences |
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CREATE SEQUENCE foo_seq; |
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ALTER TABLE foo_seq RENAME TO foo_seq_new; |
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SELECT * FROM foo_seq_new; |
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DROP SEQUENCE foo_seq_new; |
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|
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-- |
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-- Alter sequence |
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-- |
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CREATE SEQUENCE sequence_test2 START WITH 32; |
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SELECT nextval('sequence_test2'); |
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ALTER SEQUENCE sequence_test2 RESTART WITH 16 |
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INCREMENT BY 4 MAXVALUE 22 MINVALUE 5 CYCLE; |
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SELECT nextval('sequence_test2'); |
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SELECT nextval('sequence_test2'); |
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SELECT nextval('sequence_test2'); |
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|
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