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fix: Allow matching on multiple patterns, check target nodes in relationships. [translator] #819

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merged 1 commit into from
Jan 7, 2025
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fix: Allow matching on multiple patterns, check target nodes in relationships. [translator] #819

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43 changes: 43 additions & 0 deletions neo4j-jdbc-it/neo4j-jdbc-it-cp/src/test/java/org/neo4j/jdbc/it/cp/TranslationIT.java
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Original file line number Diff line number Diff line change
Expand Up @@ -356,6 +356,49 @@ void innerJoinWrongColumn() throws SQLException, IOException {

}

@Test // GH-814
void multipleHops() throws SQLException {
try (var connection = getConnection(true, false)) {
var createGraph = """
/*+ NEO4J FORCE_CYPHER */
CREATE (p:Person {name: 'A'})
CREATE (pr:Project {serial: '1'})
CREATE (c:Company {name: 'B'})
CREATE (p)-[:PARTICIPATES_IN]->(pr)
CREATE (p)-[:WORKS_FOR]->(c);
""";

var sql = """
SELECT a.*,c.*,e.*
FROM Person a
JOIN Person_PARTICIPATES_IN_Project b
ON b."v$person_id" = a."v$id"
JOIN Project c
ON c."v$id" = b."v$project_id"
JOIN Person_WORKS_FOR_Company d
ON d."v$person_id"= a."v$id"
JOIN Company e
ON e."v$id" = d."v$company_id"
""";

try (var statement = connection.createStatement()) {
statement.executeUpdate(createGraph);
}

var cypher = connection.nativeSQL(sql);
assertThat(cypher).isEqualTo(
"MATCH (a:Person)-[b:PARTICIPATES_IN]->(c:Project), (a)-[d:WORKS_FOR]->(e:Company) RETURN elementId(a) AS `v$id`, a.name AS name, elementId(c) AS `v$id1`, c.serial AS serial, elementId(e) AS `v$id2`, e.name AS name1");
try (var statement = connection.createStatement(); var result = statement.executeQuery(sql)) {
assertThat(result.next()).isTrue();
assertThat(result.getString("name")).isEqualTo("A");
assertThat(result.getString("name1")).isEqualTo("B");
assertThat(result.next()).isFalse();
}

}

}

record PersonAndTitle(String name, String title) {
}

Expand Down
78 changes: 52 additions & 26 deletions neo4j-jdbc-translator/impl/src/main/java/org/neo4j/jdbc/translator/impl/SqlToCypher.java
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Original file line number Diff line number Diff line change
Expand Up @@ -310,7 +310,7 @@ private Statement statement(QOM.Delete<?> d) {
this.tables.clear();
this.tables.add(d.$from());

Node e = (Node) resolveTableOrJoin(this.tables.get(0));
Node e = (Node) resolveTableOrJoinf(this.tables.get(0)).get(0);
OngoingReadingWithoutWhere m1 = Cypher.match(e);
OngoingReadingWithWhere m2 = (d.$where() != null) ? m1.where(condition(d.$where()))
: (OngoingReadingWithWhere) m1;
Expand All @@ -321,7 +321,7 @@ private Statement statement(QOM.Truncate<?> t) {
this.tables.clear();
this.tables.addAll(t.$table());

Node e = (Node) resolveTableOrJoin(this.tables.get(0));
Node e = (Node) resolveTableOrJoinf(this.tables.get(0)).get(0);
return Cypher.match(e).detachDelete(e.asExpression()).build();
}

Expand Down Expand Up @@ -350,7 +350,8 @@ private ResultStatement statement(Select<?> incoming) {
return Cypher.returning(resultColumnsSupplier.get()).build();
}

OngoingReadingWithoutWhere m1 = Cypher.match(x.$from().stream().map(this::resolveTableOrJoin).toList());
OngoingReadingWithoutWhere m1 = Cypher
.match(x.$from().stream().flatMap(t -> resolveTableOrJoinf(t).stream()).toList());
OngoingReadingWithWhere m2 = (x.$where() != null) ? m1.where(condition(x.$where()))
: (OngoingReadingWithWhere) m1;

Expand All @@ -377,7 +378,7 @@ private Statement statement(QOM.Insert<?> insert, List<? extends SelectFieldOrAs
this.tables.clear();
this.tables.add(insert.$into());

var node = (Node) this.resolveTableOrJoin(this.tables.get(0));
var node = (Node) this.resolveTableOrJoinf(this.tables.get(0)).get(0);
var rows = insert.$values();

var hasMergeProperties = !insert.$onConflict().isEmpty();
Expand Down Expand Up @@ -513,7 +514,7 @@ private Statement statement(QOM.Update<?> update) {
this.tables.clear();
this.tables.add(update.$table());

var node = (Node) this.resolveTableOrJoin(this.tables.get(0));
var node = (Node) this.resolveTableOrJoinf(this.tables.get(0)).get(0);
var updates = new ArrayList<Expression>();
update.$set().forEach((c, v) -> {
updates.add(node.property(((Field<?>) c).getName()));
Expand Down Expand Up @@ -555,7 +556,7 @@ else if (t instanceof Asterisk) {
}
return properties.stream();
}
else if (t instanceof QualifiedAsterisk q && resolveTableOrJoin(q.$table()) instanceof Node node) {
else if (t instanceof QualifiedAsterisk q && resolveTableOrJoinf(q.$table()).get(0) instanceof Node node) {

var properties = new ArrayList<Expression>();
for (var table : this.tables) {
Expand Down Expand Up @@ -586,7 +587,7 @@ private List<Expression> projectAllColumns(List<Table<?>> from) {
return properties;
}
for (Table<?> table : from) {
var pc = (PropertyContainer) resolveTableOrJoin(table);
var pc = (PropertyContainer) resolveTableOrJoinf(table).get(0);
var tableName = labelOrType(table);
if (!(pc instanceof Relationship rel)) {
properties.addAll(findProperties(tableName, pc));
Expand Down Expand Up @@ -696,7 +697,7 @@ private SortItem expression(SortField<?> s) {
private Expression findTableFieldInTables(TableField<?, ?> tf, boolean fallbackToFieldName) {
Expression col = null;
if (this.tables.size() == 1) {
var propertyContainer = (PropertyContainer) resolveTableOrJoin(this.tables.get(0));
var propertyContainer = (PropertyContainer) resolveTableOrJoinf(this.tables.get(0)).get(0);
if (isElementId(tf)) {
return makeId(propertyContainer, tf.getName());
}
Expand All @@ -721,19 +722,19 @@ else if (this.databaseMetaData != null) {

// Figure out virtual columns
if (isId) {
var pc = (PropertyContainer) resolveTableOrJoin(table);
var pc = (PropertyContainer) resolveTableOrJoinf(table).get(0);
return makeId(pc, tf.getName());
}
if (tableName.equalsIgnoreCase(prefix)) {
var pc = (PropertyContainer) resolveTableOrJoin(table);
var pc = (PropertyContainer) resolveTableOrJoinf(table).get(0);
return makeId(pc, tf.getName());
}

try (var columns = this.databaseMetaData.getColumns(null, null, tableName, null)) {
while (columns.next()) {
var columnName = columns.getString("COLUMN_NAME");
if (columnName.equals(tf.getName())) {
var pc = (PropertyContainer) resolveTableOrJoin(table);
var pc = (PropertyContainer) resolveTableOrJoinf(table).get(0);
col = pc.property(tf.getName());
}
}
Expand Down Expand Up @@ -783,7 +784,7 @@ else if (f instanceof TableField<?, ?> tf) {
return tableField;
}

var pe = resolveTableOrJoin(tf.getTable());
var pe = resolveTableOrJoinf(tf.getTable()).get(0);
if (pe instanceof PropertyContainer pc) {
var m = ELEMENT_ID_PATTERN.matcher(tf.getName());
if (m.matches()) {
Expand Down Expand Up @@ -1225,27 +1226,28 @@ private Condition rowCondition(Row r1, Row r2,
return result;
}

private PatternElement resolveTableOrJoin(Table<?> t) {
private List<PatternElement> resolveTableOrJoinf(Table<?> t) {
var relationship = this.resolvedRelationships.get(Cypher.name(t.getName()));
if (relationship != null) {
return relationship;
return List.of(relationship);
}

if (t instanceof QOM.JoinTable<?, ? extends Table<?>> joinTable) {
return resolveJoin(joinTable);
}

if (t instanceof TableAlias<?> ta) {
var resolved = resolveTableOrJoin(ta.$aliased());
var patternElements = resolveTableOrJoinf(ta.$aliased());
var resolved = (patternElements.size() == 1) ? patternElements.get(0) : null;
if ((resolved instanceof Node || resolved instanceof Relationship) && !ta.$alias().empty()) {
return nodeOrPattern(ta.$aliased(), ta.$alias().last());
return List.of(nodeOrPattern(ta.$aliased(), ta.$alias().last()));
}
else {
throw unsupported(ta);
}
}
else {
return nodeOrPattern(t, t.getName());
return List.of(nodeOrPattern(t, t.getName()));
}
}

Expand Down Expand Up @@ -1277,7 +1279,7 @@ private PatternElement nodeOrPattern(Table<?> t, String name) {
return Cypher.node(primaryLabel).named(symbolicName);
}

private RelationshipPattern resolveJoin(QOM.JoinTable<?, ? extends Table<?>> joinTable) {
private List<PatternElement> resolveJoin(QOM.JoinTable<?, ? extends Table<?>> joinTable) {
var join = JoinDetails.of(joinTable);

String relType = null;
Expand All @@ -1287,9 +1289,9 @@ private RelationshipPattern resolveJoin(QOM.JoinTable<?, ? extends Table<?>> joi

Table<?> t1 = joinTable.$table1();
if (t1 instanceof QOM.JoinTable<?, ? extends Table<?>> lhsJoin) {
lhs = resolveTableOrJoin(lhsJoin.$table1());
lhs = resolveTableOrJoinf(lhsJoin.$table1()).get(0);
var eqJoin2 = JoinDetails.of(lhsJoin);
var relationship = tryToIntegrateNodeAndVirtualTable(lhs, resolveTableOrJoin(lhsJoin.$table2()),
var relationship = tryToIntegrateNodeAndVirtualTable(lhs, resolveTableOrJoinf(lhsJoin.$table2()).get(0),
eqJoin2.eq);
if (relationship != null) {
lhs = relationship;
Expand All @@ -1302,27 +1304,50 @@ private RelationshipPattern resolveJoin(QOM.JoinTable<?, ? extends Table<?>> joi
}
}
else if (join.eq != null) {
lhs = resolveTableOrJoin(t1);
lhs = resolveTableOrJoinf(t1).get(0);
relType = type(t1, join.eq.$arg2());
}
else if (join.join != null && join.join.$using().isEmpty()) {
throw unsupported(joinTable);
}
else {
lhs = resolveTableOrJoin(t1);
lhs = resolveTableOrJoinf(t1).get(0);
relType = (join.join != null) ? type(t1, join.join.$using().get(0)) : null;
}

if (relSymbolicName == null && relType != null) {
relSymbolicName = symbolicName(relType);
}

PatternElement rhs = resolveTableOrJoin(joinTable.$table2());
PatternElement rhs = resolveTableOrJoinf(joinTable.$table2()).get(0);

if (lhs instanceof ExposesRelationships<?> from && rhs instanceof Node to) {
var relationship = tryToIntegrateNodeAndVirtualTable(lhs, rhs, join.eq);
if (relationship != null) {
return relationship;
return List.of(relationship);
}

List<PatternElement> resolved = new ArrayList<>();

// Figure out the left most driving table of the join and check if it's in
// the relationship
Table<?> leftMost = joinTable.$table1();
while (leftMost instanceof QOM.JoinTable<?, ?> tab) {
leftMost = tab.$table1();
}
var hlp = resolveTableOrJoinf(leftMost).get(0);
// We have one single previous relationship, the left most node matching
// the leftmost table and the previous table is a join table.
// Future safety check might actually be comparing the equals operators,
// too.
if (from instanceof Relationship r && hlp instanceof Node leftMostNode
&& r.getLeft().getRequiredSymbolicName().equals(leftMostNode.getRequiredSymbolicName())
&& joinTable.$table1() instanceof QOM.JoinTable<?, ?> previousJoinTable
&& nodeOrPattern(previousJoinTable.$table2(),
"ignored") instanceof Relationship targetRelationship) {
resolved.add(lhs);
from = leftMostNode;
relType = targetRelationship.getDetails().getTypes().get(0);
}

var direction = Relationship.Direction.LTR;
Expand All @@ -1341,12 +1366,13 @@ else if (relationship instanceof RelationshipChain r) {
}
this.resolvedRelationships.put(relSymbolicName, relationship);
}
return relationship;
resolved.add(relationship);
return resolved;
}
else {
var relationship = tryToIntegrateNodeAndVirtualTable(lhs, rhs, join.eq);
if (relationship != null) {
return relationship;
return List.of(relationship);
}
}

Expand Down
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