@ -3,7 +3,7 @@
* back to source text
*
* IDENTIFICATION
* $ Header : / cvsroot / pgsql / src / backend / utils / adt / ruleutils . c , v 1.115 2002 / 08 / 16 20 : 55 : 0 9 tgl Exp $
* $ Header : / cvsroot / pgsql / src / backend / utils / adt / ruleutils . c , v 1.116 2002 / 08 / 16 23 : 01 : 1 9 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg .
*
@ -40,10 +40,14 @@
# include <unistd.h>
# include <fcntl.h>
# include "access/genam.h"
# include "catalog/catname.h"
# include "catalog/heap.h"
# include "catalog/index.h"
# include "catalog/indexing.h"
# include "catalog/namespace.h"
# include "catalog/pg_cast.h"
# include "catalog/pg_constraint.h"
# include "catalog/pg_index.h"
# include "catalog/pg_opclass.h"
# include "catalog/pg_operator.h"
@ -60,6 +64,8 @@
# include "parser/parsetree.h"
# include "rewrite/rewriteManip.h"
# include "rewrite/rewriteSupport.h"
# include "utils/array.h"
# include "utils/fmgroids.h"
# include "utils/lsyscache.h"
@ -116,6 +122,8 @@ static char *query_getviewrule = "SELECT * FROM pg_catalog.pg_rewrite WHERE ev_c
* - - - - - - - - - -
*/
static text * pg_do_getviewdef ( Oid viewoid ) ;
static void decompile_column_index_array ( Datum column_index_array , Oid relId ,
StringInfo buf ) ;
static void make_ruledef ( StringInfo buf , HeapTuple ruletup , TupleDesc rulettc ) ;
static void make_viewdef ( StringInfo buf , HeapTuple ruletup , TupleDesc rulettc ) ;
static void get_query_def ( Query * query , StringInfo buf , List * parentnamespace ,
@ -528,6 +536,214 @@ pg_get_indexdef(PG_FUNCTION_ARGS)
}
/*
* pg_get_constraintdef
*
* Returns the definition for the constraint , ie , everything that needs to
* appear after " ALTER TABLE ... ADD CONSTRAINT <constraintname> " .
*
* XXX The present implementation only works for foreign - key constraints , but
* it could and should handle anything pg_constraint stores .
*/
Datum
pg_get_constraintdef ( PG_FUNCTION_ARGS )
{
Oid constraintId = PG_GETARG_OID ( 0 ) ;
text * result ;
StringInfoData buf ;
int len ;
Relation conDesc ;
SysScanDesc conscan ;
ScanKeyData skey [ 1 ] ;
HeapTuple tup ;
Form_pg_constraint conForm ;
/*
* Fetch the pg_constraint row . There ' s no syscache for pg_constraint
* so we must do it the hard way .
*/
conDesc = heap_openr ( ConstraintRelationName , AccessShareLock ) ;
ScanKeyEntryInitialize ( & skey [ 0 ] , 0x0 ,
ObjectIdAttributeNumber , F_OIDEQ ,
ObjectIdGetDatum ( constraintId ) ) ;
conscan = systable_beginscan ( conDesc , ConstraintOidIndex , true ,
SnapshotNow , 1 , skey ) ;
tup = systable_getnext ( conscan ) ;
if ( ! HeapTupleIsValid ( tup ) )
elog ( ERROR , " Failed to find constraint with OID %u " , constraintId ) ;
conForm = ( Form_pg_constraint ) GETSTRUCT ( tup ) ;
initStringInfo ( & buf ) ;
switch ( conForm - > contype )
{
case CONSTRAINT_FOREIGN :
{
Datum val ;
bool isnull ;
const char * string ;
/* Start off the constraint definition */
appendStringInfo ( & buf , " FOREIGN KEY ( " ) ;
/* Fetch and build referencing-column list */
val = heap_getattr ( tup , Anum_pg_constraint_conkey ,
RelationGetDescr ( conDesc ) , & isnull ) ;
if ( isnull )
elog ( ERROR , " pg_get_constraintdef: Null conkey for constraint %u " ,
constraintId ) ;
decompile_column_index_array ( val , conForm - > conrelid , & buf ) ;
/* add foreign relation name */
appendStringInfo ( & buf , " ) REFERENCES %s( " ,
generate_relation_name ( conForm - > confrelid ) ) ;
/* Fetch and build referenced-column list */
val = heap_getattr ( tup , Anum_pg_constraint_confkey ,
RelationGetDescr ( conDesc ) , & isnull ) ;
if ( isnull )
elog ( ERROR , " pg_get_constraintdef: Null confkey for constraint %u " ,
constraintId ) ;
decompile_column_index_array ( val , conForm - > confrelid , & buf ) ;
appendStringInfo ( & buf , " ) " ) ;
/* Add match type */
switch ( conForm - > confmatchtype )
{
case FKCONSTR_MATCH_FULL :
string = " MATCH FULL " ;
break ;
case FKCONSTR_MATCH_PARTIAL :
string = " MATCH PARTIAL " ;
break ;
case FKCONSTR_MATCH_UNSPECIFIED :
string = " " ;
break ;
default :
elog ( ERROR , " pg_get_constraintdef: Unknown confmatchtype '%c' for constraint %u " ,
conForm - > confmatchtype , constraintId ) ;
string = " " ; /* keep compiler quiet */
break ;
}
appendStringInfo ( & buf , " %s " , string ) ;
/* Add ON UPDATE and ON DELETE clauses */
switch ( conForm - > confupdtype )
{
case FKCONSTR_ACTION_NOACTION :
string = " NO ACTION " ;
break ;
case FKCONSTR_ACTION_RESTRICT :
string = " RESTRICT " ;
break ;
case FKCONSTR_ACTION_CASCADE :
string = " CASCADE " ;
break ;
case FKCONSTR_ACTION_SETNULL :
string = " SET NULL " ;
break ;
case FKCONSTR_ACTION_SETDEFAULT :
string = " SET DEFAULT " ;
break ;
default :
elog ( ERROR , " pg_get_constraintdef: Unknown confupdtype '%c' for constraint %u " ,
conForm - > confupdtype , constraintId ) ;
string = " " ; /* keep compiler quiet */
break ;
}
appendStringInfo ( & buf , " ON UPDATE %s " , string ) ;
switch ( conForm - > confdeltype )
{
case FKCONSTR_ACTION_NOACTION :
string = " NO ACTION " ;
break ;
case FKCONSTR_ACTION_RESTRICT :
string = " RESTRICT " ;
break ;
case FKCONSTR_ACTION_CASCADE :
string = " CASCADE " ;
break ;
case FKCONSTR_ACTION_SETNULL :
string = " SET NULL " ;
break ;
case FKCONSTR_ACTION_SETDEFAULT :
string = " SET DEFAULT " ;
break ;
default :
elog ( ERROR , " pg_get_constraintdef: Unknown confdeltype '%c' for constraint %u " ,
conForm - > confdeltype , constraintId ) ;
string = " " ; /* keep compiler quiet */
break ;
}
appendStringInfo ( & buf , " ON DELETE %s " , string ) ;
break ;
}
/*
* XXX Add more code here for other contypes
*/
default :
elog ( ERROR , " pg_get_constraintdef: unsupported constraint type '%c' " ,
conForm - > contype ) ;
break ;
}
/* Record the results */
len = buf . len + VARHDRSZ ;
result = ( text * ) palloc ( len ) ;
VARATT_SIZEP ( result ) = len ;
memcpy ( VARDATA ( result ) , buf . data , buf . len ) ;
/* Cleanup */
pfree ( buf . data ) ;
systable_endscan ( conscan ) ;
heap_close ( conDesc , AccessShareLock ) ;
PG_RETURN_TEXT_P ( result ) ;
}
/*
* Convert an int16 [ ] Datum into a comma - separated list of column names
* for the indicated relation ; append the list to buf .
*/
static void
decompile_column_index_array ( Datum column_index_array , Oid relId ,
StringInfo buf )
{
Datum * keys ;
int nKeys ;
int j ;
/* Extract data from array of int16 */
deconstruct_array ( DatumGetArrayTypeP ( column_index_array ) ,
true , 2 , ' s ' ,
& keys , & nKeys ) ;
for ( j = 0 ; j < nKeys ; j + + )
{
char * colName ;
colName = get_attname ( relId , DatumGetInt16 ( keys [ j ] ) ) ;
if ( j = = 0 )
appendStringInfo ( buf , " %s " ,
quote_identifier ( colName ) ) ;
else
appendStringInfo ( buf , " , %s " ,
quote_identifier ( colName ) ) ;
}
}
/* ----------
* get_expr - Decompile an expression tree
*
Tom Lane
23 years ago