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Add IF NOT EXISTS processing to ALTER TABLE ADD COLUMN
Fabrízio de Royes Mello, reviewed by Payal Singh, Alvaro Herrera and Michael Paquier.
This commit is contained in:
Andrew Dunstan
parent
632cd9f892
commit
2cd40adb85
@ -36,7 +36,7 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
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<phrase>where <replaceable class="PARAMETER">action</replaceable> is one of:</phrase>
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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> [ ... ] ]
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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> [ ... ] ]
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DROP [ COLUMN ] [ IF EXISTS ] <replaceable class="PARAMETER">column_name</replaceable> [ RESTRICT | CASCADE ]
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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> ]
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ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET DEFAULT <replaceable class="PARAMETER">expression</replaceable>
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@ -96,11 +96,13 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
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<variablelist>
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<varlistentry>
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<term><literal>ADD COLUMN</literal></term>
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<term><literal>ADD COLUMN [ IF NOT EXISTS ]</literal></term>
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<listitem>
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<para>
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This form adds a new column to the table, using the same syntax as
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<xref linkend="SQL-CREATETABLE">.
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<xref linkend="SQL-CREATETABLE">. If <literal>IF NOT EXISTS</literal>
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is specified and a column already exists with this name,
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no error is thrown.
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</para>
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</listitem>
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</varlistentry>
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@ -328,8 +328,9 @@ static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recu
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bool is_view, AlterTableCmd *cmd, LOCKMODE lockmode);
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static ObjectAddress ATExecAddColumn(List **wqueue, AlteredTableInfo *tab,
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Relation rel, ColumnDef *colDef, bool isOid,
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bool recurse, bool recursing, LOCKMODE lockmode);
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static void check_for_column_name_collision(Relation rel, const char *colname);
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bool recurse, bool recursing, bool if_not_exists, LOCKMODE lockmode);
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static bool check_for_column_name_collision(Relation rel, const char *colname,
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bool if_not_exists);
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static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
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static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid);
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static void ATPrepAddOids(List **wqueue, Relation rel, bool recurse,
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@ -2304,7 +2305,7 @@ renameatt_internal(Oid myrelid,
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oldattname)));
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/* new name should not already exist */
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check_for_column_name_collision(targetrelation, newattname);
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(void) check_for_column_name_collision(targetrelation, newattname, false);
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/* apply the update */
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namestrcpy(&(attform->attname), newattname);
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@ -3455,11 +3456,11 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
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case AT_AddColumnToView: /* add column via CREATE OR REPLACE
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* VIEW */
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address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
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false, false, false, lockmode);
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false, false, false, false, lockmode);
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break;
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case AT_AddColumnRecurse:
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address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
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false, true, false, lockmode);
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false, true, false, cmd->missing_ok, lockmode);
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break;
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case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
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address = ATExecColumnDefault(rel, cmd->name, cmd->def, lockmode);
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@ -3572,14 +3573,14 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
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if (cmd->def != NULL)
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address =
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ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
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true, false, false, lockmode);
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true, false, false, cmd->missing_ok, lockmode);
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break;
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case AT_AddOidsRecurse: /* SET WITH OIDS */
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/* Use the ADD COLUMN code, unless prep decided to do nothing */
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if (cmd->def != NULL)
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address =
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ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
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true, true, false, lockmode);
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true, true, false, cmd->missing_ok, lockmode);
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break;
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case AT_DropOids: /* SET WITHOUT OIDS */
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@ -4677,7 +4678,7 @@ ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
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static ObjectAddress
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ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
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ColumnDef *colDef, bool isOid,
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bool recurse, bool recursing, LOCKMODE lockmode)
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bool recurse, bool recursing, bool if_not_exists, LOCKMODE lockmode)
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{
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Oid myrelid = RelationGetRelid(rel);
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Relation pgclass,
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@ -4771,8 +4772,14 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
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elog(ERROR, "cache lookup failed for relation %u", myrelid);
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relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind;
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/* new name should not already exist */
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check_for_column_name_collision(rel, colDef->colname);
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/* skip if the name already exists and if_not_exists is true */
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if (!check_for_column_name_collision(rel, colDef->colname, if_not_exists))
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{
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heap_close(attrdesc, RowExclusiveLock);
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heap_freetuple(reltup);
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heap_close(pgclass, RowExclusiveLock);
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return InvalidObjectAddress;
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}
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/* Determine the new attribute's number */
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if (isOid)
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@ -5002,7 +5009,8 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
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/* Recurse to child; return value is ignored */
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ATExecAddColumn(wqueue, childtab, childrel,
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colDef, isOid, recurse, true, lockmode);
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colDef, isOid, recurse, true,
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if_not_exists, lockmode);
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heap_close(childrel, NoLock);
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}
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@ -5013,10 +5021,11 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
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/*
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* If a new or renamed column will collide with the name of an existing
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* column, error out.
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* column and if_not_exists is false then error out, else do nothing.
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*/
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static void
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check_for_column_name_collision(Relation rel, const char *colname)
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static bool
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check_for_column_name_collision(Relation rel, const char *colname,
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bool if_not_exists)
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{
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HeapTuple attTuple;
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int attnum;
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@ -5029,7 +5038,7 @@ check_for_column_name_collision(Relation rel, const char *colname)
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ObjectIdGetDatum(RelationGetRelid(rel)),
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PointerGetDatum(colname));
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if (!HeapTupleIsValid(attTuple))
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return;
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return true;
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attnum = ((Form_pg_attribute) GETSTRUCT(attTuple))->attnum;
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ReleaseSysCache(attTuple);
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@ -5045,12 +5054,25 @@ check_for_column_name_collision(Relation rel, const char *colname)
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errmsg("column name \"%s\" conflicts with a system column name",
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colname)));
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else
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{
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if (if_not_exists)
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{
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ereport(NOTICE,
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(errcode(ERRCODE_DUPLICATE_COLUMN),
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errmsg("column \"%s\" of relation \"%s\" already exists, skipping",
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colname, RelationGetRelationName(rel))));
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return false;
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}
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ereport(ERROR,
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(errcode(ERRCODE_DUPLICATE_COLUMN),
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errmsg("column \"%s\" of relation \"%s\" already exists",
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colname, RelationGetRelationName(rel))));
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}
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return true;
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}
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/*
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* Install a column's dependency on its datatype.
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*/
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@ -1942,6 +1942,16 @@ alter_table_cmd:
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AlterTableCmd *n = makeNode(AlterTableCmd);
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n->subtype = AT_AddColumn;
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n->def = $2;
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n->missing_ok = false;
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$$ = (Node *)n;
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}
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/* ALTER TABLE <name> ADD IF NOT EXISTS <coldef> */
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| ADD_P IF_P NOT EXISTS columnDef
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{
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AlterTableCmd *n = makeNode(AlterTableCmd);
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n->subtype = AT_AddColumn;
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n->def = $5;
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n->missing_ok = true;
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$$ = (Node *)n;
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}
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/* ALTER TABLE <name> ADD COLUMN <coldef> */
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@ -1950,6 +1960,16 @@ alter_table_cmd:
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AlterTableCmd *n = makeNode(AlterTableCmd);
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n->subtype = AT_AddColumn;
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n->def = $3;
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n->missing_ok = false;
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$$ = (Node *)n;
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}
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/* ALTER TABLE <name> ADD COLUMN IF NOT EXISTS <coldef> */
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| ADD_P COLUMN IF_P NOT EXISTS columnDef
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{
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AlterTableCmd *n = makeNode(AlterTableCmd);
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n->subtype = AT_AddColumn;
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n->def = $6;
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n->missing_ok = true;
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$$ = (Node *)n;
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}
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/* ALTER TABLE <name> ALTER [COLUMN] <colname> {SET DEFAULT <expr>|DROP DEFAULT} */
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@ -2605,3 +2605,92 @@ ALTER TABLE logged1 SET UNLOGGED; -- silently do nothing
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DROP TABLE logged3;
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DROP TABLE logged2;
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DROP TABLE logged1;
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-- test ADD COLUMN IF NOT EXISTS
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CREATE TABLE test_add_column(c1 integer);
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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ALTER TABLE test_add_column
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ADD COLUMN c2 integer;
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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c2 | integer |
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ALTER TABLE test_add_column
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ADD COLUMN c2 integer; -- fail because c2 already exists
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ERROR: column "c2" of relation "test_add_column" already exists
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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c2 | integer |
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer; -- skipping because c2 already exists
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NOTICE: column "c2" of relation "test_add_column" already exists, skipping
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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c2 | integer |
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ALTER TABLE test_add_column
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ADD COLUMN c2 integer, -- fail because c2 already exists
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ADD COLUMN c3 integer;
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ERROR: column "c2" of relation "test_add_column" already exists
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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c2 | integer |
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists
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ADD COLUMN c3 integer; -- fail because c3 already exists
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NOTICE: column "c2" of relation "test_add_column" already exists, skipping
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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c2 | integer |
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c3 | integer |
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists
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ADD COLUMN IF NOT EXISTS c3 integer; -- skipping because c3 already exists
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NOTICE: column "c2" of relation "test_add_column" already exists, skipping
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NOTICE: column "c3" of relation "test_add_column" already exists, skipping
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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c2 | integer |
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c3 | integer |
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists
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ADD COLUMN IF NOT EXISTS c3 integer, -- skipping because c3 already exists
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ADD COLUMN c4 integer;
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NOTICE: column "c2" of relation "test_add_column" already exists, skipping
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NOTICE: column "c3" of relation "test_add_column" already exists, skipping
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\d test_add_column
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Table "public.test_add_column"
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Column | Type | Modifiers
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--------+---------+-----------
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c1 | integer |
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c2 | integer |
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c3 | integer |
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c4 | integer |
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DROP TABLE test_add_column;
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@ -1724,3 +1724,34 @@ ALTER TABLE logged1 SET UNLOGGED; -- silently do nothing
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DROP TABLE logged3;
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DROP TABLE logged2;
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DROP TABLE logged1;
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-- test ADD COLUMN IF NOT EXISTS
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CREATE TABLE test_add_column(c1 integer);
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\d test_add_column
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ALTER TABLE test_add_column
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ADD COLUMN c2 integer;
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\d test_add_column
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ALTER TABLE test_add_column
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ADD COLUMN c2 integer; -- fail because c2 already exists
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\d test_add_column
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer; -- skipping because c2 already exists
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\d test_add_column
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ALTER TABLE test_add_column
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ADD COLUMN c2 integer, -- fail because c2 already exists
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ADD COLUMN c3 integer;
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\d test_add_column
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists
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ADD COLUMN c3 integer; -- fail because c3 already exists
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\d test_add_column
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists
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ADD COLUMN IF NOT EXISTS c3 integer; -- skipping because c3 already exists
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\d test_add_column
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ALTER TABLE test_add_column
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ADD COLUMN IF NOT EXISTS c2 integer, -- skipping because c2 already exists
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ADD COLUMN IF NOT EXISTS c3 integer, -- skipping because c3 already exists
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ADD COLUMN c4 integer;
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\d test_add_column
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DROP TABLE test_add_column;
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