@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $ Header : / cvsroot / pgsql / src / backend / commands / Attic / command . c , v 1.141 2001 / 08 / 21 16 : 36 : 01 tgl Exp $
* $ Header : / cvsroot / pgsql / src / backend / commands / Attic / command . c , v 1.142 2001 / 09 / 07 21 : 57 : 53 momjian Exp $
*
* NOTES
* The PerformAddAttribute ( ) code , like most of the relation
@ -32,6 +32,7 @@
# include "catalog/pg_type.h"
# include "commands/command.h"
# include "commands/trigger.h"
# include "commands/defrem.h" /* For add constraint unique, primary */
# include "executor/execdefs.h"
# include "executor/executor.h"
# include "miscadmin.h"
@ -42,6 +43,7 @@
# include "parser/parse_expr.h"
# include "parser/parse_oper.h"
# include "parser/parse_relation.h"
# include "parser/analyze.h" /* For add constraint unique, primary */
# include "utils/acl.h"
# include "utils/builtins.h"
# include "utils/fmgroids.h"
@ -1339,11 +1341,160 @@ AlterTableAddConstraint(char *relationName,
break ;
}
case CONSTR_PRIMARY :
case CONSTR_UNIQUE :
{
break ;
}
char * iname = constr - > name ;
bool istemp = is_temp_rel_name ( relationName ) ;
Relation rel ;
List * indexoidlist ;
List * indexoidscan ;
Form_pg_attribute * rel_attrs ;
int num_keys = 0 ;
int keys_matched = 0 ;
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) */
rel = heap_openr ( relationName , AccessExclusiveLock ) ;
/*
* First we check for limited correctness of the
* constraint
*/
rel_attrs = rel - > rd_att - > attrs ;
/* Retrieve the oids of all indices on the relation */
indexoidlist = RelationGetIndexList ( rel ) ;
index_found = false ;
index_found_unique = false ;
index_found_primary = false ;
/* Loop over all indices on the relation */
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 ) ;
keys_matched = 0 ;
if ( i = = num_keys )
{
/* Loop over each key in the constraint and check that there is a
corresponding key in the index . */
i = 0 ;
foreach ( keyl , constr - > keys )
{
Ident * key = lfirst ( keyl ) ;
/* 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 ( i < INDEX_MAX_KEYS & & indexStruct - > indkey [ i ] ! = 0 )
{
int keyno = indexStruct - > indkey [ i ] ;
if ( keyno > 0 )
{
char * name = NameStr ( rel_attrs [ keyno - 1 ] - > attname ) ;
if ( strcmp ( name , key - > name ) = = 0 ) keys_matched + + ;
}
}
else elog ( ERROR , " ALTER TABLE/ADD CONSTRAINT: Key \" %u[%u] \" not found " , indexoid , i ) ;
i + + ;
}
if ( keys_matched = = num_keys ) {
index_found = true ;
index_found_unique = indexStruct - > indisunique ;
index_found_primary = indexStruct - > indisprimary ;
if ( index_found_unique | | index_found_primary ) break ;
}
}
ReleaseSysCache ( indexTuple ) ;
}
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 ) ;
/* Finally, close relation */
heap_close ( rel , NoLock ) ;
break ;
}
default :
elog ( ERROR , " ALTER TABLE / ADD CONSTRAINT is not implemented for that constraint type. " ) ;
}
Bruce Momjian
24 years ago