Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * parse_graphtable.c
4 : * parsing of GRAPH_TABLE
5 : *
6 : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/parser/parse_graphtable.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 :
16 : #include "postgres.h"
17 :
18 : #include "access/genam.h"
19 : #include "access/htup_details.h"
20 : #include "access/table.h"
21 : #include "catalog/pg_propgraph_label.h"
22 : #include "catalog/pg_propgraph_property.h"
23 : #include "miscadmin.h"
24 : #include "nodes/makefuncs.h"
25 : #include "parser/parse_collate.h"
26 : #include "parser/parse_expr.h"
27 : #include "parser/parse_graphtable.h"
28 : #include "parser/parse_node.h"
29 : #include "utils/fmgroids.h"
30 : #include "utils/lsyscache.h"
31 : #include "utils/relcache.h"
32 : #include "utils/syscache.h"
33 :
34 :
35 : /*
36 : * Return human-readable name of the type of graph element pattern in
37 : * GRAPH_TABLE clause, usually for error message purpose.
38 : */
39 : static const char *
40 4 : get_gep_kind_name(GraphElementPatternKind gepkind)
41 : {
42 4 : switch (gepkind)
43 : {
44 0 : case VERTEX_PATTERN:
45 0 : return "vertex";
46 0 : case EDGE_PATTERN_LEFT:
47 0 : return "edge pointing left";
48 0 : case EDGE_PATTERN_RIGHT:
49 0 : return "edge pointing right";
50 0 : case EDGE_PATTERN_ANY:
51 0 : return "edge pointing any direction";
52 4 : case PAREN_EXPR:
53 4 : return "nested path pattern";
54 : }
55 :
56 : /*
57 : * When a GraphElementPattern is constructed by the parser, it will set a
58 : * value from the GraphElementPatternKind enum. But we may get here if the
59 : * GraphElementPatternKind value stored in a catalog is corrupted.
60 : */
61 0 : return "unknown";
62 : }
63 :
64 : /*
65 : * Transform a property reference.
66 : *
67 : * A property reference is parsed as a ColumnRef of the form:
68 : * <variable>.<property>. If <variable> is one of the variables bound to an
69 : * element pattern in the graph pattern and <property> can be resolved as a
70 : * property of the property graph, then we return a GraphPropertyRef node
71 : * representing the property reference. If the <variable> exists in the graph
72 : * pattern but <property> does not exist in the property graph, we raise an
73 : * error. However, if <variable> does not exist in the graph pattern, we return
74 : * NULL to let the caller handle it as some other kind of ColumnRef. The
75 : * variables bound to the element patterns in the graph pattern are expected to
76 : * be collected in the GraphTableParseState.
77 : */
78 : Node *
79 24429 : transformGraphTablePropertyRef(ParseState *pstate, ColumnRef *cref)
80 : {
81 24429 : GraphTableParseState *gpstate = pstate->p_graph_table_pstate;
82 :
83 24429 : if (!gpstate)
84 22796 : return NULL;
85 :
86 1633 : if (list_length(cref->fields) == 2)
87 : {
88 1620 : Node *field1 = linitial(cref->fields);
89 1620 : Node *field2 = lsecond(cref->fields);
90 : char *elvarname;
91 : char *propname;
92 :
93 1620 : if (IsA(field1, A_Star) || IsA(field2, A_Star))
94 : {
95 8 : if (pstate->p_expr_kind == EXPR_KIND_SELECT_TARGET)
96 4 : ereport(ERROR,
97 : errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
98 : errmsg("\"*\" is not supported here"),
99 : parser_errposition(pstate, cref->location));
100 : else
101 4 : ereport(ERROR,
102 : errcode(ERRCODE_SYNTAX_ERROR),
103 : errmsg("\"*\" not allowed here"),
104 : parser_errposition(pstate, cref->location));
105 : }
106 :
107 1612 : elvarname = strVal(field1);
108 1612 : propname = strVal(field2);
109 :
110 1612 : if (list_member(gpstate->variables, field1))
111 : {
112 1608 : GraphPropertyRef *gpr = makeNode(GraphPropertyRef);
113 : HeapTuple pgptup;
114 : Form_pg_propgraph_property pgpform;
115 :
116 1608 : pgptup = SearchSysCache2(PROPGRAPHPROPNAME, ObjectIdGetDatum(gpstate->graphid), CStringGetDatum(propname));
117 1608 : if (!HeapTupleIsValid(pgptup))
118 4 : ereport(ERROR,
119 : errcode(ERRCODE_SYNTAX_ERROR),
120 : errmsg("property \"%s\" does not exist", propname));
121 1604 : pgpform = (Form_pg_propgraph_property) GETSTRUCT(pgptup);
122 :
123 1604 : gpr->location = cref->location;
124 1604 : gpr->elvarname = elvarname;
125 1604 : gpr->propid = pgpform->oid;
126 1604 : gpr->typeId = pgpform->pgptypid;
127 1604 : gpr->typmod = pgpform->pgptypmod;
128 1604 : gpr->collation = pgpform->pgpcollation;
129 :
130 1604 : ReleaseSysCache(pgptup);
131 :
132 1604 : return (Node *) gpr;
133 : }
134 : }
135 :
136 17 : return NULL;
137 : }
138 :
139 : /*
140 : * Transform a label expression.
141 : *
142 : * A label expression is parsed as either a ColumnRef with a single field or a
143 : * label expression like label disjunction. The single field in the ColumnRef is
144 : * treated as a label name and transformed to a GraphLabelRef node. The label
145 : * expression is recursively transformed into an expression tree containg
146 : * GraphLabelRef nodes corresponding to the names of the labels appearing in the
147 : * expression. If any label name cannot be resolved to a label in the property
148 : * graph, an error is raised.
149 : */
150 : static Node *
151 1706 : transformLabelExpr(GraphTableParseState *gpstate, Node *labelexpr)
152 : {
153 : Node *result;
154 :
155 1706 : if (labelexpr == NULL)
156 629 : return NULL;
157 :
158 1077 : check_stack_depth();
159 :
160 1077 : switch (nodeTag(labelexpr))
161 : {
162 1025 : case T_ColumnRef:
163 : {
164 1025 : ColumnRef *cref = (ColumnRef *) labelexpr;
165 : const char *labelname;
166 : Oid labelid;
167 : GraphLabelRef *lref;
168 :
169 : Assert(list_length(cref->fields) == 1);
170 1025 : labelname = strVal(linitial(cref->fields));
171 :
172 1025 : labelid = GetSysCacheOid2(PROPGRAPHLABELNAME, Anum_pg_propgraph_label_oid, ObjectIdGetDatum(gpstate->graphid), CStringGetDatum(labelname));
173 1025 : if (!labelid)
174 4 : ereport(ERROR,
175 : errcode(ERRCODE_UNDEFINED_OBJECT),
176 : errmsg("label \"%s\" does not exist in property graph \"%s\"", labelname, get_rel_name(gpstate->graphid)));
177 :
178 1021 : lref = makeNode(GraphLabelRef);
179 1021 : lref->labelid = labelid;
180 1021 : lref->location = cref->location;
181 :
182 1021 : result = (Node *) lref;
183 1021 : break;
184 : }
185 :
186 52 : case T_BoolExpr:
187 : {
188 52 : BoolExpr *be = (BoolExpr *) labelexpr;
189 : ListCell *lc;
190 52 : List *args = NIL;
191 :
192 156 : foreach(lc, be->args)
193 : {
194 108 : Node *arg = (Node *) lfirst(lc);
195 :
196 108 : arg = transformLabelExpr(gpstate, arg);
197 104 : args = lappend(args, arg);
198 : }
199 :
200 48 : result = (Node *) makeBoolExpr(be->boolop, args, be->location);
201 48 : break;
202 : }
203 :
204 0 : default:
205 : /* should not reach here */
206 0 : elog(ERROR, "unsupported label expression node: %d", (int) nodeTag(labelexpr));
207 : result = NULL; /* keep compiler quiet */
208 : break;
209 : }
210 :
211 1069 : return result;
212 : }
213 :
214 : /*
215 : * Transform a GraphElementPattern.
216 : *
217 : * Transform the label expression and the where clause in the element pattern
218 : * given by GraphElementPattern. The variable name in the GraphElementPattern is
219 : * added to the list of variables in the GraphTableParseState which is used to
220 : * resolve property references in this element pattern or elsewhere in the
221 : * GRAPH_TABLE.
222 : */
223 : static Node *
224 1606 : transformGraphElementPattern(ParseState *pstate, GraphElementPattern *gep)
225 : {
226 1606 : GraphTableParseState *gpstate = pstate->p_graph_table_pstate;
227 :
228 1606 : if (gep->kind != VERTEX_PATTERN && !IS_EDGE_PATTERN(gep->kind))
229 4 : ereport(ERROR,
230 : errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
231 : errmsg("unsupported element pattern kind: \"%s\"", get_gep_kind_name(gep->kind)));
232 :
233 1602 : if (gep->quantifier)
234 4 : ereport(ERROR,
235 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
236 : errmsg("element pattern quantifier is not supported")));
237 :
238 1598 : if (gep->variable)
239 1315 : gpstate->variables = lappend(gpstate->variables, makeString(pstrdup(gep->variable)));
240 :
241 1598 : gep->labelexpr = transformLabelExpr(gpstate, gep->labelexpr);
242 :
243 1594 : gep->whereClause = transformExpr(pstate, gep->whereClause, EXPR_KIND_WHERE);
244 1590 : assign_expr_collations(pstate, gep->whereClause);
245 :
246 1590 : return (Node *) gep;
247 : }
248 :
249 : /*
250 : * Transform a path term (list of GraphElementPattern's).
251 : */
252 : static Node *
253 524 : transformPathTerm(ParseState *pstate, List *path_term)
254 : {
255 524 : List *result = NIL;
256 :
257 2622 : foreach_node(GraphElementPattern, gep, path_term)
258 1590 : result = lappend(result,
259 1606 : transformGraphElementPattern(pstate, gep));
260 :
261 508 : return (Node *) result;
262 : }
263 :
264 : /*
265 : * Transform a path pattern list (list of path terms).
266 : */
267 : static Node *
268 528 : transformPathPatternList(ParseState *pstate, List *path_pattern)
269 : {
270 528 : List *result = NIL;
271 :
272 : /* Grammar doesn't allow empty path pattern list */
273 : Assert(list_length(path_pattern) > 0);
274 :
275 : /*
276 : * We do not support multiple path patterns in one GRAPH_TABLE clause
277 : * right now. But we may do so in future.
278 : */
279 528 : if (list_length(path_pattern) != 1)
280 4 : ereport(ERROR,
281 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
282 : errmsg("multiple path patterns in one GRAPH_TABLE clause not supported")));
283 :
284 1540 : foreach_node(List, path_term, path_pattern)
285 524 : result = lappend(result, transformPathTerm(pstate, path_term));
286 :
287 508 : return (Node *) result;
288 : }
289 :
290 : /*
291 : * Transform a GraphPattern.
292 : *
293 : * A GraphPattern consists of a list of one or more path patterns and an
294 : * optional where clause. Transform them. We use the previously constructure
295 : * list of variables in the GraphTableParseState to resolve property references
296 : * in the WHERE clause.
297 : */
298 : Node *
299 528 : transformGraphPattern(ParseState *pstate, GraphPattern *graph_pattern)
300 : {
301 528 : List *path_pattern_list = castNode(List,
302 : transformPathPatternList(pstate, graph_pattern->path_pattern_list));
303 :
304 508 : graph_pattern->path_pattern_list = path_pattern_list;
305 508 : graph_pattern->whereClause = transformExpr(pstate, graph_pattern->whereClause, EXPR_KIND_WHERE);
306 508 : assign_expr_collations(pstate, graph_pattern->whereClause);
307 :
308 508 : return (Node *) graph_pattern;
309 : }
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