Support Edge Labels in CREATE Clause

Author: JoshInnis

regress/expected/cypher_create.out

@@ -143,13 +143,26 @@ MATCH (a) RETURN a;
  {"id": 1688849860263937, "label": "test2", "properties": {}}
 (3 rows)
 
+MATCH (a:test) RETURN a;
+                              a                              
+-------------------------------------------------------------
+ {"id": 1125899906842625, "label": "test", "properties": {}}
+(1 row)
+
 CREATE ()-[]->();
 WARNING:  relcache reference leak: relation "_ag_label_vertex" not closed
 WARNING:  relcache reference leak: relation "_ag_label_vertex" not closed
 WARNING:  relcache reference leak: relation "_ag_label_edge" not closed
 --
 (0 rows)
 
+CREATE ()-[:elabel]->();
+WARNING:  relcache reference leak: relation "_ag_label_vertex" not closed
+WARNING:  relcache reference leak: relation "_ag_label_vertex" not closed
+WARNING:  relcache reference leak: relation "elabel" not closed
+--
+(0 rows)
+
 EXPLAIN MATCH ()-[]->() RETURN 1;
                                              QUERY PLAN                                              
 -----------------------------------------------------------------------------------------------------
@@ -164,43 +177,48 @@ EXPLAIN MATCH ()-[]->() RETURN 1;
 EXPLAIN ANALYZE MATCH ()-[]->() RETURN 1;
                                                                   QUERY PLAN                                                                   
 -----------------------------------------------------------------------------------------------------------------------------------------------
- Nested Loop  (cost=12.50..50471.30 rows=2520000 width=32) (actual time=0.046..0.207 rows=1 loops=1)
-   ->  Append  (cost=0.00..58.80 rows=2520 width=8) (actual time=0.005..0.013 rows=5 loops=1)
-         ->  Seq Scan on _ag_label_vertex _age_default_alias_0_1  (cost=0.00..2.20 rows=120 width=8) (actual time=0.005..0.006 rows=3 loops=1)
-         ->  Seq Scan on test _age_default_alias_0_2  (cost=0.00..22.00 rows=1200 width=8) (actual time=0.001..0.002 rows=1 loops=1)
-         ->  Seq Scan on test2 _age_default_alias_0_3  (cost=0.00..22.00 rows=1200 width=8) (actual time=0.002..0.002 rows=1 loops=1)
-   ->  Function Scan on edge_search _age_default_alias_1  (cost=12.50..22.50 rows=1000 width=0) (actual time=0.037..0.037 rows=0 loops=5)
- Planning Time: 0.093 ms
- Execution Time: 0.231 ms
+ Nested Loop  (cost=12.50..50471.30 rows=2520000 width=32) (actual time=0.057..0.302 rows=2 loops=1)
+   ->  Append  (cost=0.00..58.80 rows=2520 width=8) (actual time=0.009..0.018 rows=7 loops=1)
+         ->  Seq Scan on _ag_label_vertex _age_default_alias_0_1  (cost=0.00..2.20 rows=120 width=8) (actual time=0.008..0.010 rows=5 loops=1)
+         ->  Seq Scan on test _age_default_alias_0_2  (cost=0.00..22.00 rows=1200 width=8) (actual time=0.002..0.003 rows=1 loops=1)
+         ->  Seq Scan on test2 _age_default_alias_0_3  (cost=0.00..22.00 rows=1200 width=8) (actual time=0.002..0.003 rows=1 loops=1)
+   ->  Function Scan on edge_search _age_default_alias_1  (cost=12.50..22.50 rows=1000 width=0) (actual time=0.039..0.039 rows=0 loops=7)
+ Planning Time: 0.126 ms
+ Execution Time: 0.332 ms
 (8 rows)
 
 MATCH ()-[]->() RETURN 1;
  ?column? 
 ----------
  1
-(1 row)
+ 1
+(2 rows)
 
 SELECT * FROM cypher_create._ag_label_vertex;
    id   | properties 
 --------+------------
  (1, 1) | 
  (1, 2) | 
  (1, 3) | 
+ (1, 4) | 
+ (1, 5) | 
  (4, 1) | 
  (6, 1) | 
-(5 rows)
+(7 rows)
 
 SELECT * FROM cypher_create._adj__adj__ag_label_vertex;
       id       | start_id | end_id | properties 
 ---------------+----------+--------+------------
- (0, 25304768) | (1, 2)   | (1, 3) | 
-(1 row)
+ (0, 36327104) | (1, 2)   | (1, 3) | 
+ (0, 35832480) | (1, 4)   | (1, 5) | 
+(2 rows)
 
 SELECT * FROM cypher_create._adj__ag_label_vertex;
       id       | start_id | end_id | properties 
 ---------------+----------+--------+------------
- (0, 25304768) | (1, 2)   | (1, 3) | 
-(1 row)
+ (0, 36327104) | (1, 2)   | (1, 3) | 
+ (0, 35832480) | (1, 4)   | (1, 5) | 
+(2 rows)
 
 MATCH () RETURN 1;
  ?column? 
@@ -210,7 +228,9 @@ MATCH () RETURN 1;
  1
  1
  1
-(5 rows)
+ 1
+ 1
+(7 rows)
 
 CYPHER WITH 1 as a
 CREATE ();
@@ -221,7 +241,7 @@ ERROR:  CREATE doesn't work with next clauses
 -- Clean up
 --
 DROP GRAPH cypher_create CASCADE;
-NOTICE:  drop cascades to 10 other objects
+NOTICE:  drop cascades to 11 other objects
 DETAIL:  drop cascades to table cypher_create._ag_label_vertex
 drop cascades to table cypher_create._adj__ag_label_vertex
 drop cascades to table cypher_create._adj__adj__ag_label_vertex
@@ -232,6 +252,7 @@ drop cascades to table cypher_create._adj__adj_test
 drop cascades to table cypher_create.test2
 drop cascades to table cypher_create._adj_test2
 drop cascades to table cypher_create._adj__adj_test2
+drop cascades to table cypher_create.elabel
 NOTICE:  graph "cypher_create" has been dropped
  drop_graph 
 ------------

regress/sql/cypher_create.sql

@@ -46,8 +46,13 @@ MATCH () RETURN 1;
 
 MATCH (a) RETURN a;
 
+MATCH (a:test) RETURN a;
+
 CREATE ()-[]->();
 
+CREATE ()-[:elabel]->();
+
+
 EXPLAIN MATCH ()-[]->() RETURN 1;
 
 EXPLAIN ANALYZE MATCH ()-[]->() RETURN 1;

src/backend/parser/cypher_clause.c

@@ -336,6 +336,26 @@ static Expr *add_volatile_wrapper(Expr *node) {
     return (Expr *)makeFuncExpr(oid, GTYPEOID, list_make1(node), InvalidOid, InvalidOid, COERCE_EXPLICIT_CALL);
 }
 
+static void validate_or_create_elabel(cypher_parsestate *cpstate, cypher_relationship *edge) {
+    ParseState *pstate = (ParseState *)cpstate;
+    label_cache_data *lcd = search_label_name_graph_cache(edge->label, cpstate->graph_oid);
+
+    if (lcd && lcd->kind != LABEL_KIND_EDGE) {
+        ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                        errmsg("label %s is for vertices, not edges", edge->label),
+                        parser_errposition(pstate, edge->location)));
+    } else if (!lcd)  {
+        List *parent;
+        RangeVar *rv;
+
+        rv = get_label_range_var(cpstate->graph_name, cpstate->graph_oid, AG_DEFAULT_LABEL_EDGE);
+
+        parent = list_make1(rv);
+
+        create_label(cpstate->graph_name, edge->label, LABEL_TYPE_EDGE, parent, NULL);
+    }
+}
+
 static void validate_or_create_vlabel(cypher_parsestate *cpstate, cypher_node *node) {
     ParseState *pstate = (ParseState *)cpstate;
     label_cache_data *lcd = search_label_name_graph_cache(node->label, cpstate->graph_oid);
@@ -423,7 +443,7 @@ static Query *transform_cypher_create(cypher_parsestate *cpstate, cypher_clause
                 cypher_relationship *edge = lfirst(lc2);
 
                 if (edge->label) 
-                    ereport(ERROR, (errmsg_internal("edges in CREATE cannot have labels")));
+                    validate_or_create_elabel(cpstate, edge);
                 else
                     edge->label = AG_DEFAULT_LABEL_EDGE;
 
@@ -1190,10 +1210,12 @@ static void transform_match_pattern(cypher_parsestate *cpstate, Query *query, Li
                     node->name = get_next_default_alias(cpstate);
 
                 bool is_default_label = true;
-                if (node->label)
+                if (node->label && i != 1)
                     ereport(ERROR,
                             (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                             errmsg("MATCH labels are not supported")));
+                else if (node->label)
+                    is_default_label = false;
                 else
                     node->label = AG_DEFAULT_LABEL_VERTEX;
 
@@ -1281,7 +1303,7 @@ static void transform_match_pattern(cypher_parsestate *cpstate, Query *query, Li
                     } else {
                         continue;
                     }
-                    //edge_pnsi = pnsi;
+
                 } 
 
                 // id field