tupdesc.c

postgresql8.3.4源码,开源数据库

		 *
		 * attcacheoff must NOT be checked since it's possibly not set in both
		 * copies.
		 */
		if (strcmp(NameStr(attr1->attname), NameStr(attr2->attname)) != 0)
			return false;
		if (attr1->atttypid != attr2->atttypid)
			return false;
		if (attr1->attstattarget != attr2->attstattarget)
			return false;
		if (attr1->attlen != attr2->attlen)
			return false;
		if (attr1->attndims != attr2->attndims)
			return false;
		if (attr1->atttypmod != attr2->atttypmod)
			return false;
		if (attr1->attbyval != attr2->attbyval)
			return false;
		if (attr1->attstorage != attr2->attstorage)
			return false;
		if (attr1->attalign != attr2->attalign)
			return false;
		if (attr1->attnotnull != attr2->attnotnull)
			return false;
		if (attr1->atthasdef != attr2->atthasdef)
			return false;
		if (attr1->attisdropped != attr2->attisdropped)
			return false;
		if (attr1->attislocal != attr2->attislocal)
			return false;
		if (attr1->attinhcount != attr2->attinhcount)
			return false;
	}

	if (tupdesc1->constr != NULL)
	{
		TupleConstr *constr1 = tupdesc1->constr;
		TupleConstr *constr2 = tupdesc2->constr;

		if (constr2 == NULL)
			return false;
		if (constr1->has_not_null != constr2->has_not_null)
			return false;
		n = constr1->num_defval;
		if (n != (int) constr2->num_defval)
			return false;
		for (i = 0; i < n; i++)
		{
			AttrDefault *defval1 = constr1->defval + i;
			AttrDefault *defval2 = constr2->defval;

			/*
			 * We can't assume that the items are always read from the system
			 * catalogs in the same order; so use the adnum field to identify
			 * the matching item to compare.
			 */
			for (j = 0; j < n; defval2++, j++)
			{
				if (defval1->adnum == defval2->adnum)
					break;
			}
			if (j >= n)
				return false;
			if (strcmp(defval1->adbin, defval2->adbin) != 0)
				return false;
		}
		n = constr1->num_check;
		if (n != (int) constr2->num_check)
			return false;
		for (i = 0; i < n; i++)
		{
			ConstrCheck *check1 = constr1->check + i;
			ConstrCheck *check2 = constr2->check;

			/*
			 * Similarly, don't assume that the checks are always read in the
			 * same order; match them up by name and contents. (The name
			 * *should* be unique, but...)
			 */
			for (j = 0; j < n; check2++, j++)
			{
				if (strcmp(check1->ccname, check2->ccname) == 0 &&
					strcmp(check1->ccbin, check2->ccbin) == 0)
					break;
			}
			if (j >= n)
				return false;
		}
	}
	else if (tupdesc2->constr != NULL)
		return false;
	return true;
}

/*
 * TupleDescInitEntry
 *		This function initializes a single attribute structure in
 *		a previously allocated tuple descriptor.
 */
void
TupleDescInitEntry(TupleDesc desc,
				   AttrNumber attributeNumber,
				   const char *attributeName,
				   Oid oidtypeid,
				   int32 typmod,
				   int attdim)
{
	HeapTuple	tuple;
	Form_pg_type typeForm;
	Form_pg_attribute att;

	/*
	 * sanity checks
	 */
	AssertArg(PointerIsValid(desc));
	AssertArg(attributeNumber >= 1);
	AssertArg(attributeNumber <= desc->natts);

	/*
	 * initialize the attribute fields
	 */
	att = desc->attrs[attributeNumber - 1];

	att->attrelid = 0;			/* dummy value */

	/*
	 * Note: attributeName can be NULL, because the planner doesn't always
	 * fill in valid resname values in targetlists, particularly for resjunk
	 * attributes.
	 */
	if (attributeName != NULL)
		namestrcpy(&(att->attname), attributeName);
	else
		MemSet(NameStr(att->attname), 0, NAMEDATALEN);

	att->attstattarget = -1;
	att->attcacheoff = -1;
	att->atttypmod = typmod;

	att->attnum = attributeNumber;
	att->attndims = attdim;

	att->attnotnull = false;
	att->atthasdef = false;
	att->attisdropped = false;
	att->attislocal = true;
	att->attinhcount = 0;

	tuple = SearchSysCache(TYPEOID,
						   ObjectIdGetDatum(oidtypeid),
						   0, 0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "cache lookup failed for type %u", oidtypeid);
	typeForm = (Form_pg_type) GETSTRUCT(tuple);

	att->atttypid = oidtypeid;
	att->attlen = typeForm->typlen;
	att->attbyval = typeForm->typbyval;
	att->attalign = typeForm->typalign;
	att->attstorage = typeForm->typstorage;

	ReleaseSysCache(tuple);
}


/*
 * BuildDescForRelation
 *
 * Given a relation schema (list of ColumnDef nodes), build a TupleDesc.
 *
 * Note: the default assumption is no OIDs; caller may modify the returned
 * TupleDesc if it wants OIDs.	Also, tdtypeid will need to be filled in
 * later on.
 */
TupleDesc
BuildDescForRelation(List *schema)
{
	int			natts;
	AttrNumber	attnum;
	ListCell   *l;
	TupleDesc	desc;
	AttrDefault *attrdef = NULL;
	TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
	char	   *attname;
	Oid			atttypid;
	int32		atttypmod;
	int			attdim;
	int			ndef = 0;

	/*
	 * allocate a new tuple descriptor
	 */
	natts = list_length(schema);
	desc = CreateTemplateTupleDesc(natts, false);
	constr->has_not_null = false;

	attnum = 0;

	foreach(l, schema)
	{
		ColumnDef  *entry = lfirst(l);

		/*
		 * for each entry in the list, get the name and type information from
		 * the list and have TupleDescInitEntry fill in the attribute
		 * information we need.
		 */
		attnum++;

		attname = entry->colname;
		atttypid = typenameTypeId(NULL, entry->typename, &atttypmod);
		attdim = list_length(entry->typename->arrayBounds);

		if (entry->typename->setof)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
					 errmsg("column \"%s\" cannot be declared SETOF",
							attname)));

		TupleDescInitEntry(desc, attnum, attname,
						   atttypid, atttypmod, attdim);

		/* Fill in additional stuff not handled by TupleDescInitEntry */
		if (entry->is_not_null)
			constr->has_not_null = true;
		desc->attrs[attnum - 1]->attnotnull = entry->is_not_null;

		/*
		 * Note we copy only pre-cooked default expressions. Digestion of raw
		 * ones is someone else's problem.
		 */
		if (entry->cooked_default != NULL)
		{
			if (attrdef == NULL)
				attrdef = (AttrDefault *) palloc(natts * sizeof(AttrDefault));
			attrdef[ndef].adnum = attnum;
			attrdef[ndef].adbin = pstrdup(entry->cooked_default);
			ndef++;
			desc->attrs[attnum - 1]->atthasdef = true;
		}

		desc->attrs[attnum - 1]->attislocal = entry->is_local;
		desc->attrs[attnum - 1]->attinhcount = entry->inhcount;
	}

	if (constr->has_not_null || ndef > 0)
	{
		desc->constr = constr;

		if (ndef > 0)			/* DEFAULTs */
		{
			if (ndef < natts)
				constr->defval = (AttrDefault *)
					repalloc(attrdef, ndef * sizeof(AttrDefault));
			else
				constr->defval = attrdef;
			constr->num_defval = ndef;
		}
		else
		{
			constr->defval = NULL;
			constr->num_defval = 0;
		}
		constr->check = NULL;
		constr->num_check = 0;
	}
	else
	{
		pfree(constr);
		desc->constr = NULL;
	}

	return desc;
}

/*
 * BuildDescFromLists
 *
 * Build a TupleDesc given lists of column names (as String nodes),
 * column type OIDs, and column typmods.  No constraints are generated.
 *
 * This is essentially a cut-down version of BuildDescForRelation for use
 * with functions returning RECORD.
 */
TupleDesc
BuildDescFromLists(List *names, List *types, List *typmods)
{
	int			natts;
	AttrNumber	attnum;
	ListCell   *l1;
	ListCell   *l2;
	ListCell   *l3;
	TupleDesc	desc;

	natts = list_length(names);
	Assert(natts == list_length(types));
	Assert(natts == list_length(typmods));

	/*
	 * allocate a new tuple descriptor
	 */
	desc = CreateTemplateTupleDesc(natts, false);

	attnum = 0;

	l2 = list_head(types);
	l3 = list_head(typmods);
	foreach(l1, names)
	{
		char	   *attname = strVal(lfirst(l1));
		Oid			atttypid;
		int32		atttypmod;

		atttypid = lfirst_oid(l2);
		l2 = lnext(l2);
		atttypmod = lfirst_int(l3);
		l3 = lnext(l3);

		attnum++;

		TupleDescInitEntry(desc, attnum, attname, atttypid, atttypmod, 0);
	}

	return desc;
}