*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.150 2001/11/05 17:46:24 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.151 2001/12/04 17:19:48 tgl Exp $
*
* NOTES
* The PerformAddAttribute() code, like most of the relation
{
Constraint *constr = (Constraint *) newConstraint;
+ /*
+ * Currently, we only expect to see CONSTR_CHECK nodes
+ * arriving here (see the preprocessing done in
+ * parser/analyze.c). Use a switch anyway to make it
+ * easier to add more code later.
+ */
switch (constr->contype)
{
case CONSTR_CHECK:
break;
}
- case CONSTR_UNIQUE:
- {
- char *iname = constr->name;
- bool istemp = is_temp_rel_name(relationName);
- List *indexoidlist;
- List *indexoidscan;
- int num_keys;
- bool index_found = false;
- bool index_found_unique = false;
- bool index_found_primary = false;
-
- /*
- * If the constraint name is not
- * specified, generate a name
- */
- if (iname == NULL)
- {
- Oid indoid;
- int pass = 0;
- char *typename = palloc(NAMEDATALEN);
- Ident *key;
-
- /*
- * Assume that the length of the attr
- * list is already > 0
- */
-
- /*
- * Get the first attribute so we can
- * use its name
- */
- key = (Ident *) lfirst(constr->keys);
-
- /* Initialise typename to 'key' */
- snprintf(typename, NAMEDATALEN, "key");
-
- for (;;)
- {
- iname = makeObjectName(relationName, key->name, typename);
-
- /* Check for a conflict */
- indoid = RelnameFindRelid(iname);
-
- /*
- * If the oid was not found, then
- * we have a safe name
- */
- if ((!istemp && !OidIsValid(indoid)) ||
- (istemp && !is_temp_rel_name(iname)))
- break;
-
- /*
- * Found a conflict, so try a new
- * name component
- */
- pfree(iname);
- snprintf(typename, NAMEDATALEN, "key%d", ++pass);
- }
- }
-
- /*
- * Need to check for unique key already on
- * field(s)
- */
-
- /*
- * First we check for limited correctness
- * of the constraint
- */
-
- /* Loop over all indices on the relation */
- indexoidlist = RelationGetIndexList(rel);
-
- foreach(indexoidscan, indexoidlist)
- {
- Oid indexoid = lfirsti(indexoidscan);
- HeapTuple indexTuple;
- Form_pg_index indexStruct;
- List *keyl;
- int i;
-
- indexTuple = SearchSysCache(INDEXRELID,
- ObjectIdGetDatum(indexoid),
- 0, 0, 0);
-
- if (!HeapTupleIsValid(indexTuple))
- elog(ERROR, "ALTER TABLE / ADD CONSTRAINT: Index \"%u\" not found",
- indexoid);
- indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
-
- /*
- * Make sure this index has the same
- * number of keys as the constraint --
- * It obviously won't match otherwise.
- */
- for (i = 0; i < INDEX_MAX_KEYS && indexStruct->indkey[i] != 0; i++)
- ;
- num_keys = length(constr->keys);
-
- if (i == num_keys)
- {
- /*
- * Loop over each key in the
- * constraint and check that there
- * is a corresponding key in the
- * index.
- */
- int keys_matched = 0;
-
- i = 0;
- foreach(keyl, constr->keys)
- {
- Ident *key = lfirst(keyl);
- int keyno = indexStruct->indkey[i];
-
- /*
- * Look at key[i] in the index
- * and check that it is over
- * the same column as key[i]
- * in the constraint. This is
- * to differentiate between
- * (a,b) and (b,a)
- */
- if (namestrcmp(attnumAttName(rel, keyno),
- key->name) == 0)
- keys_matched++;
- else
- break;
- i++;
- }
- if (keys_matched == num_keys)
- {
- index_found = true;
- index_found_unique = indexStruct->indisunique;
- index_found_primary = indexStruct->indisprimary;
- }
- }
- ReleaseSysCache(indexTuple);
- if (index_found_unique || index_found_primary)
- break;
- }
-
- freeList(indexoidlist);
-
- if (index_found_primary)
- elog(ERROR, "Unique primary key already defined on relation \"%s\"", relationName);
- else if (index_found_unique)
- elog(ERROR, "Unique constraint already defined on the specified attributes in relation \"%s\"", relationName);
-
- /*
- * If everything is ok, create the new
- * index (constraint)
- */
- DefineIndex(
- relationName,
- iname,
- "btree",
- constr->keys,
- true,
- false,
- NULL,
- NIL);
-
- /* Issue notice */
- elog(NOTICE, "ALTER TABLE / ADD UNIQUE will create implicit index '%s' for table '%s'",
- iname, relationName);
- if (index_found)
- elog(NOTICE, "Unique constraint supercedes existing index on relation \"%s\". Drop the existing index to remove redundancy.", relationName);
- pfree(iname);
-
- break;
- }
default:
elog(ERROR, "ALTER TABLE / ADD CONSTRAINT is not implemented for that constraint type.");
}
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