Hi all, This simple patch add CINE for ALTER TABLE ... ADD COLUMN.
So now we can: ALTER TABLE foo ADD COLUMN IF NOT EXISTS c1 integer; and/or ... ALTER TABLE foo ADD COLUMN IF NOT EXISTS c1 integer, ADD COLUMN c2 integer; Regards, -- Fabrízio de Royes Mello Consultoria/Coaching PostgreSQL >> Timbira: http://www.timbira.com.br >> Blog: http://fabriziomello.github.io >> Linkedin: http://br.linkedin.com/in/fabriziomello >> Twitter: http://twitter.com/fabriziomello >> Github: http://github.com/fabriziomello
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml index b3a4970..aba7ec0 100644 --- a/doc/src/sgml/ref/alter_table.sgml +++ b/doc/src/sgml/ref/alter_table.sgml @@ -36,7 +36,7 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable> <phrase>where <replaceable class="PARAMETER">action</replaceable> is one of:</phrase> - ADD [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ COLLATE <replaceable class="PARAMETER">collation</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ] + ADD [ COLUMN ] [ IF NOT EXISTS ]<replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ COLLATE <replaceable class="PARAMETER">collation</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ] DROP [ COLUMN ] [ IF EXISTS ] <replaceable class="PARAMETER">column_name</replaceable> [ RESTRICT | CASCADE ] ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> [ SET DATA ] TYPE <replaceable class="PARAMETER">data_type</replaceable> [ COLLATE <replaceable class="PARAMETER">collation</replaceable> ] [ USING <replaceable class="PARAMETER">expression</replaceable> ] ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET DEFAULT <replaceable class="PARAMETER">expression</replaceable> @@ -96,11 +96,12 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable> <variablelist> <varlistentry> - <term><literal>ADD COLUMN</literal></term> + <term><literal>ADD COLUMN [ IF NOT EXISTS ]</literal></term> <listitem> <para> This form adds a new column to the table, using the same syntax as - <xref linkend="SQL-CREATETABLE">. + <xref linkend="SQL-CREATETABLE">. If <literal>IF NOT EXISTS</literal> + is specified and the column already exists, no error is thrown. </para> </listitem> </varlistentry> diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index f5d5b63..5ecb438 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -328,8 +328,8 @@ static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recu AlterTableCmd *cmd, LOCKMODE lockmode); static void ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel, ColumnDef *colDef, bool isOid, - bool recurse, bool recursing, LOCKMODE lockmode); -static void check_for_column_name_collision(Relation rel, const char *colname); + bool recurse, bool recursing, bool if_not_exists, LOCKMODE lockmode); +static bool check_for_column_name_collision(Relation rel, const char *colname, bool if_not_exists); static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid); static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid); static void ATPrepAddOids(List **wqueue, Relation rel, bool recurse, @@ -2283,7 +2283,7 @@ renameatt_internal(Oid myrelid, oldattname))); /* new name should not already exist */ - check_for_column_name_collision(targetrelation, newattname); + check_for_column_name_collision(targetrelation, newattname, false); /* apply the update */ namestrcpy(&(attform->attname), newattname); @@ -3399,11 +3399,11 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel, case AT_AddColumnToView: /* add column via CREATE OR REPLACE * VIEW */ ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def, - false, false, false, lockmode); + false, false, false, cmd->missing_ok, lockmode); break; case AT_AddColumnRecurse: ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def, - false, true, false, lockmode); + false, true, false, cmd->missing_ok, lockmode); break; case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */ ATExecColumnDefault(rel, cmd->name, cmd->def, lockmode); @@ -3500,13 +3500,13 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel, /* Use the ADD COLUMN code, unless prep decided to do nothing */ if (cmd->def != NULL) ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def, - true, false, false, lockmode); + true, false, false, cmd->missing_ok, lockmode); break; case AT_AddOidsRecurse: /* SET WITH OIDS */ /* Use the ADD COLUMN code, unless prep decided to do nothing */ if (cmd->def != NULL) ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def, - true, true, false, lockmode); + true, true, false, cmd->missing_ok, lockmode); break; case AT_DropOids: /* SET WITHOUT OIDS */ @@ -4593,7 +4593,7 @@ ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing, static void ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel, ColumnDef *colDef, bool isOid, - bool recurse, bool recursing, LOCKMODE lockmode) + bool recurse, bool recursing, bool if_not_exists, LOCKMODE lockmode) { Oid myrelid = RelationGetRelid(rel); Relation pgclass, @@ -4687,7 +4687,13 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel, relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind; /* new name should not already exist */ - check_for_column_name_collision(rel, colDef->colname); + if (!check_for_column_name_collision(rel, colDef->colname, if_not_exists)) + { + heap_close(attrdesc, RowExclusiveLock); + heap_freetuple(reltup); + heap_close(pgclass, RowExclusiveLock); + return; + } /* Determine the new attribute's number */ if (isOid) @@ -4917,7 +4923,8 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel, /* Recurse to child */ ATExecAddColumn(wqueue, childtab, childrel, - colDef, isOid, recurse, true, lockmode); + colDef, isOid, recurse, true, + if_not_exists, lockmode); heap_close(childrel, NoLock); } @@ -4927,8 +4934,8 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel, * If a new or renamed column will collide with the name of an existing * column, error out. */ -static void -check_for_column_name_collision(Relation rel, const char *colname) +static bool +check_for_column_name_collision(Relation rel, const char *colname, bool if_not_exists) { HeapTuple attTuple; int attnum; @@ -4941,7 +4948,7 @@ check_for_column_name_collision(Relation rel, const char *colname) ObjectIdGetDatum(RelationGetRelid(rel)), PointerGetDatum(colname)); if (!HeapTupleIsValid(attTuple)) - return; + return true; attnum = ((Form_pg_attribute) GETSTRUCT(attTuple))->attnum; ReleaseSysCache(attTuple); @@ -4957,10 +4964,23 @@ check_for_column_name_collision(Relation rel, const char *colname) errmsg("column name \"%s\" conflicts with a system column name", colname))); else + { + if (if_not_exists) + { + ereport(NOTICE, + (errcode(ERRCODE_DUPLICATE_COLUMN), + errmsg("column \"%s\" of relation \"%s\" already exists, skipping", + colname, RelationGetRelationName(rel)))); + return false; + } + ereport(ERROR, (errcode(ERRCODE_DUPLICATE_COLUMN), errmsg("column \"%s\" of relation \"%s\" already exists", colname, RelationGetRelationName(rel)))); + } + + return true; } /* diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 581f7a1..4761029 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -1921,6 +1921,16 @@ alter_table_cmd: AlterTableCmd *n = makeNode(AlterTableCmd); n->subtype = AT_AddColumn; n->def = $2; + n->missing_ok = false; + $$ = (Node *)n; + } + /* ALTER TABLE <name> ADD IF NOT EXISTS <coldef> */ + | ADD_P IF_P NOT EXISTS columnDef + { + AlterTableCmd *n = makeNode(AlterTableCmd); + n->subtype = AT_AddColumn; + n->def = $5; + n->missing_ok = true; $$ = (Node *)n; } /* ALTER TABLE <name> ADD COLUMN <coldef> */ @@ -1929,6 +1939,16 @@ alter_table_cmd: AlterTableCmd *n = makeNode(AlterTableCmd); n->subtype = AT_AddColumn; n->def = $3; + n->missing_ok = false; + $$ = (Node *)n; + } + /* ALTER TABLE <name> ADD COLUMN IF NOT EXISTS <coldef> */ + | ADD_P COLUMN IF_P NOT EXISTS columnDef + { + AlterTableCmd *n = makeNode(AlterTableCmd); + n->subtype = AT_AddColumn; + n->def = $6; + n->missing_ok = true; $$ = (Node *)n; } /* ALTER TABLE <name> ALTER [COLUMN] <colname> {SET DEFAULT <expr>|DROP DEFAULT} */ diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out index d233710..bc6108e 100644 --- a/src/test/regress/expected/alter_table.out +++ b/src/test/regress/expected/alter_table.out @@ -2534,3 +2534,92 @@ ALTER TABLE logged1 SET UNLOGGED; -- silently do nothing DROP TABLE logged3; DROP TABLE logged2; DROP TABLE logged1; +-- test ADD COLUMN IF NOT EXISTS +CREATE TABLE test_add_column(c1 integer); +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + +ALTER TABLE test_add_column + ADD COLUMN c2 integer; +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + c2 | integer | + +ALTER TABLE test_add_column + ADD COLUMN c2 integer; -- fail because c2 already exists +ERROR: column "c2" of relation "test_add_column" already exists +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + c2 | integer | + +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer; -- skipping because c2 already exists +NOTICE: column "c2" of relation "test_add_column" already exists, skipping +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + c2 | integer | + +ALTER TABLE test_add_column + ADD COLUMN c2 integer, -- fail because c2 already exists + ADD COLUMN c3 integer; +ERROR: column "c2" of relation "test_add_column" already exists +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + c2 | integer | + +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists + ADD COLUMN c3 integer; -- fail because c3 already exists +NOTICE: column "c2" of relation "test_add_column" already exists, skipping +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + c2 | integer | + c3 | integer | + +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists + ADD COLUMN IF NOT EXISTS c3 integer; -- skipping because c3 already exists +NOTICE: column "c2" of relation "test_add_column" already exists, skipping +NOTICE: column "c3" of relation "test_add_column" already exists, skipping +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + c2 | integer | + c3 | integer | + +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists + ADD COLUMN IF NOT EXISTS c3 integer, -- skipping because c3 already exists + ADD COLUMN c4 integer; +NOTICE: column "c2" of relation "test_add_column" already exists, skipping +NOTICE: column "c3" of relation "test_add_column" already exists, skipping +\d test_add_column +Table "public.test_add_column" + Column | Type | Modifiers +--------+---------+----------- + c1 | integer | + c2 | integer | + c3 | integer | + c4 | integer | + +DROP TABLE test_add_column; diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql index d0d29ee..db26279 100644 --- a/src/test/regress/sql/alter_table.sql +++ b/src/test/regress/sql/alter_table.sql @@ -1686,3 +1686,34 @@ ALTER TABLE logged1 SET UNLOGGED; -- silently do nothing DROP TABLE logged3; DROP TABLE logged2; DROP TABLE logged1; + +-- test ADD COLUMN IF NOT EXISTS +CREATE TABLE test_add_column(c1 integer); +\d test_add_column +ALTER TABLE test_add_column + ADD COLUMN c2 integer; +\d test_add_column +ALTER TABLE test_add_column + ADD COLUMN c2 integer; -- fail because c2 already exists +\d test_add_column +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer; -- skipping because c2 already exists +\d test_add_column +ALTER TABLE test_add_column + ADD COLUMN c2 integer, -- fail because c2 already exists + ADD COLUMN c3 integer; +\d test_add_column +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists + ADD COLUMN c3 integer; -- fail because c3 already exists +\d test_add_column +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists + ADD COLUMN IF NOT EXISTS c3 integer; -- skipping because c3 already exists +\d test_add_column +ALTER TABLE test_add_column + ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists + ADD COLUMN IF NOT EXISTS c3 integer, -- skipping because c3 already exists + ADD COLUMN c4 integer; +\d test_add_column +DROP TABLE test_add_column;
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