diff options
author | Tom Lane | 2008-12-15 21:35:31 +0000 |
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committer | Tom Lane | 2008-12-15 21:35:31 +0000 |
commit | c1374dac4e0dc5b27d9e735b30d4c782b94c325f (patch) | |
tree | 04ce8ff6e2bf56384c7e208060caf726d329f560 | |
parent | 2cc52beed87a06af102c5019704e7de5f6a8562c (diff) |
Code review for CREATE OR REPLACE VIEW patch. Do things in a saner order to
result in hopefully-less-confusing error messages when the new definition
isn't compatible with the old; minor other cleanup.
-rw-r--r-- | doc/src/sgml/ref/create_view.sgml | 11 | ||||
-rw-r--r-- | src/backend/commands/tablecmds.c | 27 | ||||
-rw-r--r-- | src/backend/commands/view.c | 40 | ||||
-rw-r--r-- | src/test/regress/expected/create_view.out | 2 |
4 files changed, 45 insertions, 35 deletions
diff --git a/doc/src/sgml/ref/create_view.sgml b/doc/src/sgml/ref/create_view.sgml index df01488c0a..2d485c33ea 100644 --- a/doc/src/sgml/ref/create_view.sgml +++ b/doc/src/sgml/ref/create_view.sgml @@ -38,9 +38,10 @@ CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW <replaceable class="PARAMETER">n <para> <command>CREATE OR REPLACE VIEW</command> is similar, but if a view of the same name already exists, it is replaced. The new query must - generate all of the same columns that were generated by the original query - in the same order and with the same data types, but may add additional - columns to the end of the list. + generate the same columns that were generated by the existing view query + (that is, the same column names in the same order and with the same data + types), but it may add additional columns to the end of the list. The + calculations giving rise to the output columns may be completely different. </para> <para> @@ -77,7 +78,7 @@ CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW <replaceable class="PARAMETER">n </para> </listitem> </varlistentry> - + <varlistentry> <term><replaceable class="parameter">name</replaceable></term> <listitem> @@ -164,7 +165,7 @@ CREATE VIEW comedies AS </programlisting> </para> </refsect1> - + <refsect1> <title>Compatibility</title> diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 8b276ae7fc..36888371ad 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -3459,9 +3459,7 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, attrdesc; HeapTuple reltup; FormData_pg_attribute attribute; - int i; - int minattnum, - maxatts; + int newattnum; char relkind; HeapTuple typeTuple; Oid typeOid; @@ -3520,6 +3518,7 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, 0, 0, 0); if (!HeapTupleIsValid(reltup)) elog(ERROR, "cache lookup failed for relation %u", myrelid); + relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind; /* * this test is deliberately not attisdropped-aware, since if one tries to @@ -3534,15 +3533,12 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, errmsg("column \"%s\" of relation \"%s\" already exists", colDef->colname, RelationGetRelationName(rel)))); - minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts; - relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind; - maxatts = minattnum + 1; - if (maxatts > MaxHeapAttributeNumber) + newattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts + 1; + if (newattnum > MaxHeapAttributeNumber) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_COLUMNS), errmsg("tables can have at most %d columns", MaxHeapAttributeNumber))); - i = minattnum + 1; typeTuple = typenameType(NULL, colDef->typename, &typmod); tform = (Form_pg_type) GETSTRUCT(typeTuple); @@ -3551,6 +3547,7 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, /* make sure datatype is legal for a column */ CheckAttributeType(colDef->colname, typeOid); + /* construct new attribute's pg_attribute entry */ attribute.attrelid = myrelid; namestrcpy(&(attribute.attname), colDef->colname); attribute.atttypid = typeOid; @@ -3558,7 +3555,7 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, attribute.attlen = tform->typlen; attribute.attcacheoff = -1; attribute.atttypmod = typmod; - attribute.attnum = i; + attribute.attnum = newattnum; attribute.attbyval = tform->typbyval; attribute.attndims = list_length(colDef->typename->arrayBounds); attribute.attstorage = tform->typstorage; @@ -3578,7 +3575,7 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, /* * Update number of attributes in pg_class tuple */ - ((Form_pg_class) GETSTRUCT(reltup))->relnatts = maxatts; + ((Form_pg_class) GETSTRUCT(reltup))->relnatts = newattnum; simple_heap_update(pgclass, &reltup->t_self, reltup); @@ -3635,9 +3632,13 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, * returned by AddRelationNewConstraints, so that the right thing happens * when a datatype's default applies. * - * We skip this logic completely for views. + * We skip this step completely for views. For a view, we can only get + * here from CREATE OR REPLACE VIEW, which historically doesn't set up + * defaults, not even for domain-typed columns. And in any case we mustn't + * invoke Phase 3 on a view, since it has no storage. */ - if (relkind != RELKIND_VIEW) { + if (relkind != RELKIND_VIEW) + { defval = (Expr *) build_column_default(rel, attribute.attnum); if (!defval && GetDomainConstraints(typeOid) != NIL) @@ -3680,7 +3681,7 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel, /* * Add needed dependency entries for the new column. */ - add_column_datatype_dependency(myrelid, i, attribute.atttypid); + add_column_datatype_dependency(myrelid, newattnum, attribute.atttypid); } /* diff --git a/src/backend/commands/view.c b/src/backend/commands/view.c index d985ac0464..a0947cd3fd 100644 --- a/src/backend/commands/view.c +++ b/src/backend/commands/view.c @@ -165,6 +165,9 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(rel)); + /* Also check it's not in use already */ + CheckTableNotInUse(rel, "CREATE OR REPLACE VIEW"); + /* * Due to the namespace visibility rules for temporary objects, we * should only end up replacing a temporary view with another @@ -173,38 +176,42 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace) Assert(relation->istemp == rel->rd_istemp); /* - * If new attributes have been added, we must modify the pre-existing - * view. - */ - if (list_length(attrList) > rel->rd_att->natts) { + * Create a tuple descriptor to compare against the existing view, and + * verify that the old column list is an initial prefix of the new + * column list. + */ + descriptor = BuildDescForRelation(attrList); + checkViewTupleDesc(descriptor, rel->rd_att); + + /* + * If new attributes have been added, we must add pg_attribute entries + * for them. It is convenient (although overkill) to use the ALTER + * TABLE ADD COLUMN infrastructure for this. + */ + if (list_length(attrList) > rel->rd_att->natts) + { List *atcmds = NIL; ListCell *c; int skip = rel->rd_att->natts; - foreach(c, attrList) { + foreach(c, attrList) + { AlterTableCmd *atcmd; - if (skip > 0) { - --skip; + if (skip > 0) + { + skip--; continue; } atcmd = makeNode(AlterTableCmd); atcmd->subtype = AT_AddColumnToView; - atcmd->def = lfirst(c); + atcmd->def = (Node *) lfirst(c); atcmds = lappend(atcmds, atcmd); } AlterTableInternal(viewOid, atcmds, true); } /* - * Create a tuple descriptor to compare against the existing view, and - * verify that the old column list is an initial prefix of the new - * column list. - */ - descriptor = BuildDescForRelation(attrList); - checkViewTupleDesc(descriptor, rel->rd_att); - - /* * Seems okay, so return the OID of the pre-existing view. */ relation_close(rel, NoLock); /* keep the lock! */ @@ -238,6 +245,7 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace) * Verify that tupledesc associated with proposed new view definition * matches tupledesc of old view. This is basically a cut-down version * of equalTupleDescs(), with code added to generate specific complaints. + * Also, we allow the new tupledesc to have more columns than the old. */ static void checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc) diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out index e9b6c83e25..90e6c70e57 100644 --- a/src/test/regress/expected/create_view.out +++ b/src/test/regress/expected/create_view.out @@ -53,7 +53,7 @@ ERROR: cannot drop columns from view -- should fail CREATE OR REPLACE VIEW viewtest AS SELECT 1, * FROM viewtest_tbl; -ERROR: column "b" of relation "viewtest" already exists +ERROR: cannot change name of view column "a" -- should fail CREATE OR REPLACE VIEW viewtest AS SELECT a, b::numeric FROM viewtest_tbl; |