Function transformPartitionBound

src/backend/parser/parse_utilcmd.c:5210–5356

* transformPartitionBound * * Transform a partition bound specification */

 * Transform a partition bound specification
 */
PartitionBoundSpec *
transformPartitionBound(ParseState *pstate, Relation parent, PartitionKey key,
						PartitionBoundSpec *spec)
{
	PartitionBoundSpec *result_spec;
	char		strategy = get_partition_strategy(key);
	int			partnatts = get_partition_natts(key);
	List	   *partexprs = get_partition_exprs(key);

	/* Avoid scribbling on input */
	result_spec = copyObject(spec);

	if (spec->is_default)
	{
		/*
		 * Hash partitioning does not support a default partition; there's no
		 * use case for it (since the set of partitions to create is perfectly
		 * defined), and if users do get into it accidentally, it's hard to
		 * back out from it afterwards.
		 */
		if (strategy == PARTITION_STRATEGY_HASH)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
					 errmsg("a hash-partitioned table may not have a default partition")));

		/*
		 * In case of the default partition, parser had no way to identify the
		 * partition strategy. Assign the parent's strategy to the default
		 * partition bound spec.
		 */
		result_spec->strategy = strategy;

		return result_spec;
	}

	if (strategy == PARTITION_STRATEGY_HASH)
	{
		if (spec->strategy != PARTITION_STRATEGY_HASH)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
					 errmsg("invalid bound specification for a hash partition"),
					 parser_errposition(pstate, exprLocation((Node *) spec))));

		if (spec->modulus <= 0)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
					 errmsg("modulus for hash partition must be an integer value greater than zero")));

		Assert(spec->remainder >= 0);

		if (spec->remainder >= spec->modulus)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
					 errmsg("remainder for hash partition must be less than modulus")));
	}
	else if (strategy == PARTITION_STRATEGY_LIST)
	{
		ListCell   *cell;