diff options
Diffstat (limited to 'src/backend/utils/adt/misc.c')
| -rw-r--r-- | src/backend/utils/adt/misc.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c index 4096faff9a1..634f574d7eb 100644 --- a/src/backend/utils/adt/misc.c +++ b/src/backend/utils/adt/misc.c @@ -25,6 +25,7 @@ #include "catalog/catalog.h" #include "catalog/pg_tablespace.h" #include "catalog/pg_type.h" +#include "catalog/system_fk_info.h" #include "commands/dbcommands.h" #include "commands/tablespace.h" #include "common/keywords.h" @@ -37,6 +38,7 @@ #include "storage/fd.h" #include "tcop/tcopprot.h" #include "utils/builtins.h" +#include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/ruleutils.h" #include "utils/timestamp.h" @@ -489,6 +491,84 @@ pg_get_keywords(PG_FUNCTION_ARGS) } +/* Function to return the list of catalog foreign key relationships */ +Datum +pg_get_catalog_foreign_keys(PG_FUNCTION_ARGS) +{ + FuncCallContext *funcctx; + FmgrInfo *arrayinp; + + if (SRF_IS_FIRSTCALL()) + { + MemoryContext oldcontext; + TupleDesc tupdesc; + + funcctx = SRF_FIRSTCALL_INIT(); + oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx); + + tupdesc = CreateTemplateTupleDesc(6); + TupleDescInitEntry(tupdesc, (AttrNumber) 1, "fktable", + REGCLASSOID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 2, "fkcols", + TEXTARRAYOID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 3, "pktable", + REGCLASSOID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 4, "pkcols", + TEXTARRAYOID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 5, "is_array", + BOOLOID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 6, "is_opt", + BOOLOID, -1, 0); + + funcctx->tuple_desc = BlessTupleDesc(tupdesc); + + /* + * We use array_in to convert the C strings in sys_fk_relationships[] + * to text arrays. But we cannot use DirectFunctionCallN to call + * array_in, and it wouldn't be very efficient if we could. Fill an + * FmgrInfo to use for the call. + */ + arrayinp = (FmgrInfo *) palloc(sizeof(FmgrInfo)); + fmgr_info(F_ARRAY_IN, arrayinp); + funcctx->user_fctx = arrayinp; + + MemoryContextSwitchTo(oldcontext); + } + + funcctx = SRF_PERCALL_SETUP(); + arrayinp = (FmgrInfo *) funcctx->user_fctx; + + if (funcctx->call_cntr < lengthof(sys_fk_relationships)) + { + const SysFKRelationship *fkrel = &sys_fk_relationships[funcctx->call_cntr]; + Datum values[6]; + bool nulls[6]; + HeapTuple tuple; + + memset(nulls, false, sizeof(nulls)); + + values[0] = ObjectIdGetDatum(fkrel->fk_table); + values[1] = FunctionCall3(arrayinp, + CStringGetDatum(fkrel->fk_columns), + ObjectIdGetDatum(TEXTOID), + Int32GetDatum(-1)); + values[2] = ObjectIdGetDatum(fkrel->pk_table); + values[3] = FunctionCall3(arrayinp, + CStringGetDatum(fkrel->pk_columns), + ObjectIdGetDatum(TEXTOID), + Int32GetDatum(-1)); + values[4] = BoolGetDatum(fkrel->is_array); + values[5] = BoolGetDatum(fkrel->is_opt); + + tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls); + + SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple)); + } + + SRF_RETURN_DONE(funcctx); +} + + /* * Return the type of the argument. */ |