add multi-col test

Author: elianddb

enginetest/queries/script_queries.go

@@ -10507,6 +10507,8 @@ where
 		SetUpScript: []string{
 			"create table parent (d decimal(4, 2) primary key);",
 			"insert into parent values (1.23), (45.67), (78.9);",
+			"create table parent_multi (d1 decimal(4,2), d2 decimal(3,1), primary key (d1, d2));",
+			"insert into parent_multi values (1.23, 4.5), (45.67, 78.9), (99.99, 0.1);",
 		},
 		Assertions: []ScriptTestAssertion{
 			{
@@ -10569,6 +10571,21 @@ where
 				Query:       "insert into child_dec_4_1 values (99.9);",
 				ExpectedErr: sql.ErrForeignKeyChildViolation,
 			},
+			{
+				Query: "create table child_multi_4_2_3_1 (d1 decimal(4,2), d2 decimal(3,1), foreign key (d1, d2) references parent_multi (d1, d2));",
+				Expected: []sql.Row{
+					{types.NewOkResult(0)},
+				}},
+			{
+				Query: "insert into child_multi_4_2_3_1 values (1.23, 4.5), (45.67, 78.9), (NULL, NULL);",
+				Expected: []sql.Row{
+					{types.NewOkResult(3)},
+				},
+			},
+			{
+				Query:       "insert into child_multi_4_2_3_1 values (1.23, 9.9);",
+				ExpectedErr: sql.ErrForeignKeyChildViolationMySQL845,
+			},
 		},
 	},
 

sql/plan/foreign_key_editor.go

@@ -541,14 +541,12 @@ func (reference *ForeignKeyReferenceHandler) CheckReference(ctx *sql.Context, ro
 		}
 	}
 
-	return sql.ErrForeignKeyChildViolation.New(reference.ForeignKey.Database, reference.ForeignKey.Table,
-		reference.ForeignKey.Name, strings.Join(reference.ForeignKey.Columns, ", "),
-		reference.ForeignKey.ParentTable, strings.Join(reference.ForeignKey.ParentColumns, ", "))
+	return sql.ErrForeignKeyChildViolation.New(reference.ForeignKey.Name, reference.ForeignKey.Table,
+		reference.ForeignKey.ParentTable, reference.RowMapper.GetKeyString(row))
 }
 
 func (reference *ForeignKeyReferenceHandler) validateDecimalMatch(ctx *sql.Context, row sql.Row) bool {
-	if reference.RowMapper.Index == nil {
-		return false
+do 		return false
 	}
 	indexColumnTypes := reference.RowMapper.Index.ColumnExpressionTypes()
 	for i := range reference.ForeignKey.Columns {
@@ -622,7 +620,6 @@ func (mapper *ForeignKeyRowMapper) GetIter(ctx *sql.Context, row sql.Row, refChe
 		}
 
 		targetType := mapper.SourceSch[rowPos].Type
-
 		// Transform the type of the value in this row to the one in the other table for the index lookup, if necessary
 		if mapper.TargetTypeConversions != nil && mapper.TargetTypeConversions[rowPos] != nil {
 			var err error