Function EnforceUniqueEntity

src/constraint/unique_constraint.c:67–213

enforces unique constraint on given entity returns true if entity confirms with constraint false otherwise

// enforces unique constraint on given entity
// returns true if entity confirms with constraint false otherwise
bool EnforceUniqueEntity
(
	const Constraint c,    // constraint to enforce
	const GraphEntity *e,  // enforced entity
	char **err_msg         // report error message
) {
	// validations
	ASSERT(c != NULL);
	ASSERT(e != NULL);

	UniqueConstraint _c = (UniqueConstraint)c;

	Index   idx     = _c->idx;
	bool    holds   = false;  // return value none-optimistic
	RSIndex *rs_idx = Index_RSIndex(idx);

	//--------------------------------------------------------------------------
	// construct a RediSearch query locating entity
	//--------------------------------------------------------------------------

	// TODO: prefer to have the RediSearch query "template" constructed
	// once and reused for each entity

	SIType t;
	SIValue *v;
	uint8_t i     = 0;
	RSQNode *node = NULL;  // RediSearch query node
	RSQNode *root = NULL;  // root of RediSearch query tree
	RSQNode *nodes[_c->n_attr];
	RSResultsIterator *iter = NULL;
	const AttributeSet attributes = GraphEntity_GetAttributes(e);

	//--------------------------------------------------------------------------
	// create a RediSearch query
	//--------------------------------------------------------------------------

	for(i = 0; i < _c->n_attr; i++) {
		Attribute_ID attr_id = _c->attrs[i];
		const char *field = _c->attr_names[i];

		// get current attribute from entity
		v = AttributeSet_Get(attributes, attr_id);
		if(v == ATTRIBUTE_NOTFOUND) {
			// entity satisfies constraint in a vacuous truth manner
			holds = true;
			goto cleanup;
		}

		// create RediSearch query node according to entity attr type
		t = SI_TYPE(*v);

		if(!(t & SI_INDEXABLE)) {
			// TODO: see RediSearch MULTI-VALUE index.
			holds = true;
			goto cleanup;
		} else if(t == T_STRING) {
			node = RediSearch_CreateTagNode(rs_idx, field);
			RSQNode *child = RediSearch_CreateTagTokenNode(rs_idx, v->stringval);