/* ----------------------------------------------------------------
* caql_getattname()
*
* The equivalent of SearchSysCacheCopyAttName -
* caql_getfirst(pCtx,
* "SELECT * FROM pg_attribute
* WHERE attrelid = :relid
* AND attname = :attname
* AND attisdropped is false"
* );
*
* That is, find the existing ("undropped") attribute and return
* a copy.
* NOTE: need to be careful if this pCtx is used for update...
* ----------------------------------------------------------------
*/
HeapTuple caql_getattname(cqContext *pCtx, Oid relid, const char *attname)
{
HeapTuple tup;
disable_attribute_check(relid);
tup = SearchSysCacheCopyAttName(relid, attname);
if (pCtx)
{
/* treat as ATTNAME cache lookup */
pCtx->cq_usesyscache = true;
pCtx->cq_cacheId = ATTNAME;
pCtx->cq_NumKeys = 2;
/* NOTE: no valid relation for subsequent INSERT/UPDATE/DELETE
*unless* an external relation is supplied */
if (!pCtx->cq_externrel)
{
pCtx->cq_externrel = true; /* pretend we have external relation */
pCtx->cq_heap_rel = InvalidRelation;
}
if (!pCtx->cq_setidxOK)
pCtx->cq_useidxOK = true;
pCtx->cq_lasttup = tup;
}
return (tup);
}
/* ----------------------------------------------------------------
* caql_getattname_scan()
*
* The equivalent of SearchSysCacheAttName -
* caql_beginscan(pCtx,
* "SELECT * FROM pg_attribute
* WHERE attrelid = :relid
* AND attname = :attname
* AND attisdropped is false"
* );
*
* That is, find the existing ("undropped") attribute and return
* a context where the tuple is already fetched. Retrieve the tuple
* using caql_get_current()
* NOTE: this is hideous. My abject apologies.
* NOTE: need to be careful if this pCtx is used for update...
* ----------------------------------------------------------------
*/
cqContext *
caql_getattname_scan(cqContext *pCtx0, Oid relid, const char *attname)
{
cqContext *pCtx;
HeapTuple tup;
disable_attribute_check(relid);
/* use the provided context, or *allocate* a clean one */
if (pCtx0)
pCtx = pCtx0;
else
{
pCtx = (cqContext *) palloc0(sizeof(cqContext));
pCtx->cq_free = true; /* free this context in caql_endscan */
}
tup = SearchSysCacheAttName(relid, attname);
if (pCtx)
{
/* treat as ATTNAME cache lookup */
pCtx->cq_usesyscache = true;
pCtx->cq_cacheId = ATTNAME;
pCtx->cq_NumKeys = 2;
/* NOTE: no valid relation for subsequent INSERT/UPDATE/DELETE
*unless* an external relation is supplied */
if (!pCtx->cq_externrel)
{
pCtx->cq_externrel = true; /* pretend we have external relation */
pCtx->cq_heap_rel = InvalidRelation;
}
if (!pCtx->cq_setidxOK)
pCtx->cq_useidxOK = true;
pCtx->cq_freeScan = true;
pCtx->cq_EOF = true;
/* for caql_update_current(), etc */
if (pCtx->cq_setpklock)
caql_iud_switch(pCtx, 0, tup, NULL, false /* Wait */);
pCtx->cq_lasttup = tup;
}
return pCtx;
}
/*
* from lsyscach.c/get_attnum():
*
* Given the relation id and the attribute name,
* return the "attnum" field from the attribute relation.
*
* Returns InvalidAttrNumber if the attr doesn't exist (or is dropped).
*/
AttrNumber caql_getattnumber(Oid relid, const char *attname)
{
HeapTuple tp;
disable_attribute_check(relid);
tp = SearchSysCacheAttName(relid, attname);
if (HeapTupleIsValid(tp))
{
Form_pg_attribute att_tup = (Form_pg_attribute) GETSTRUCT(tp);
AttrNumber result;
result = att_tup->attnum;
ReleaseSysCache(tp);
return result;
}
else
return InvalidAttrNumber;
}