Enable multiple expressions with database events

It is now possible to run multiple query expressions when an event on a table has occured. Query expressions can be separated with a semicolon, and will be run in the same transaction as the main query.

db/check.go

@@ -192,9 +192,9 @@ func (d *document) allow(ctx context.Context, when method) (ok bool, err error)
 // table, and executes them in name order.
 func (d *document) event(ctx context.Context, when method) (err error) {
 
-	// Get the index values specified
+	// Get the event values specified
 	// for this table, loop through
-	// them, and compute the changes.
+	// them, and compute the events.
 
 	evs, err := d.getEV()
 	if err != nil {

db/define_test.go

@@ -378,22 +378,24 @@ func TestDefine(t *testing.T) {
 
 		txt := `
 		USE NS test DB test;
-		DEFINE EVENT test ON person WHEN test > 1000 THEN (CREATE temp);
+		DEFINE EVENT test ON person WHEN test > 1000 THEN (CREATE temp; CREATE test);
 		UPDATE person:test SET test = 1000;
 		UPDATE person:test SET test = 4000;
 		UPDATE person:test SET test = 2000;
 		UPDATE person:test SET test = 6000;
 		SELECT * FROM temp;
+		SELECT * FROM test;
 		`
 
 		res, err := Execute(setupKV(), txt, nil)
 		So(err, ShouldBeNil)
-		So(res, ShouldHaveLength, 7)
+		So(res, ShouldHaveLength, 8)
 		So(res[2].Result, ShouldHaveLength, 1)
 		So(res[3].Result, ShouldHaveLength, 1)
 		So(res[4].Result, ShouldHaveLength, 1)
 		So(res[5].Result, ShouldHaveLength, 1)
 		So(res[6].Result, ShouldHaveLength, 3)
+		So(res[7].Result, ShouldHaveLength, 3)
 
 	})
 
@@ -403,22 +405,24 @@ func TestDefine(t *testing.T) {
 
 		txt := `
 		USE NS test DB test;
-		DEFINE EVENT test ON person WHEN $before.test < $after.test THEN (CREATE temp);
+		DEFINE EVENT test ON person WHEN $before.test < $after.test THEN (CREATE temp; CREATE test);
 		UPDATE person:test SET test = 1000;
 		UPDATE person:test SET test = 4000;
 		UPDATE person:test SET test = 2000;
 		UPDATE person:test SET test = 6000;
 		SELECT * FROM temp;
+		SELECT * FROM test;
 		`
 
 		res, err := Execute(setupKV(), txt, nil)
 		So(err, ShouldBeNil)
-		So(res, ShouldHaveLength, 7)
+		So(res, ShouldHaveLength, 8)
 		So(res[2].Result, ShouldHaveLength, 1)
 		So(res[3].Result, ShouldHaveLength, 1)
 		So(res[4].Result, ShouldHaveLength, 1)
 		So(res[5].Result, ShouldHaveLength, 1)
 		So(res[6].Result, ShouldHaveLength, 2)
+		So(res[7].Result, ShouldHaveLength, 2)
 
 	})
 
@@ -428,22 +432,24 @@ func TestDefine(t *testing.T) {
 
 		txt := `
 		USE NS test DB test;
-		DEFINE EVENT test ON person WHEN $before.test < 5000 AND $after.test > 5000 THEN (CREATE temp);
+		DEFINE EVENT test ON person WHEN $before.test < 5000 AND $after.test > 5000 THEN (CREATE temp; CREATE test);
 		UPDATE person:test SET test = 1000;
 		UPDATE person:test SET test = 4000;
 		UPDATE person:test SET test = 2000;
 		UPDATE person:test SET test = 6000;
 		SELECT * FROM temp;
+		SELECT * FROM test;
 		`
 
 		res, err := Execute(setupKV(), txt, nil)
 		So(err, ShouldBeNil)
-		So(res, ShouldHaveLength, 7)
+		So(res, ShouldHaveLength, 8)
 		So(res[2].Result, ShouldHaveLength, 1)
 		So(res[3].Result, ShouldHaveLength, 1)
 		So(res[4].Result, ShouldHaveLength, 1)
 		So(res[5].Result, ShouldHaveLength, 1)
 		So(res[6].Result, ShouldHaveLength, 1)
+		So(res[7].Result, ShouldHaveLength, 1)
 
 	})
 
@@ -473,7 +479,7 @@ func TestDefine(t *testing.T) {
 
 		txt := `
 		USE NS test DB test;
-		DEFINE EVENT test ON person WHEN true THEN false;
+		DEFINE EVENT test ON person WHEN true THEN (CREATE test);
 		SELECT * FROM person;
 		`
 

db/fetch.go

@@ -180,6 +180,35 @@ func (e *executor) fetch(ctx context.Context, val interface{}, doc *data.Doc) (o
 			return e.fetchUpsert(ctx, exp, doc)
 		}
 
+	case *sql.MultExpression:
+
+		for _, exp := range val.Expr {
+
+			switch exp := exp.(type) {
+			case *sql.SelectStatement:
+				out, err = e.fetchSelect(ctx, exp, doc)
+			case *sql.CreateStatement:
+				out, err = e.fetchCreate(ctx, exp, doc)
+			case *sql.UpdateStatement:
+				out, err = e.fetchUpdate(ctx, exp, doc)
+			case *sql.DeleteStatement:
+				out, err = e.fetchDelete(ctx, exp, doc)
+			case *sql.RelateStatement:
+				out, err = e.fetchRelate(ctx, exp, doc)
+			case *sql.InsertStatement:
+				out, err = e.fetchInsert(ctx, exp, doc)
+			case *sql.UpsertStatement:
+				out, err = e.fetchUpsert(ctx, exp, doc)
+			}
+
+			if err != nil {
+				return out, err
+			}
+
+		}
+
+		return nil, nil
+
 	case *sql.PathExpression:
 
 		return e.fetchPaths(ctx, doc, val.Expr...)

db/info_test.go

@@ -114,7 +114,7 @@ func TestInfo(t *testing.T) {
 
 		txt := `
 		USE NS test DB test;
-		DEFINE EVENT test ON test WHEN true THEN null;
+		DEFINE EVENT test ON test WHEN true THEN (CREATE test);
 		DEFINE FIELD test ON test;
 		DEFINE INDEX test ON test COLUMNS id;
 		INFO FOR TABLE test;
@@ -132,7 +132,7 @@ func TestInfo(t *testing.T) {
 		So(res[3].Status, ShouldEqual, "OK")
 		So(res[4].Status, ShouldEqual, "OK")
 		So(data.Consume(res[4].Result[0]).Get("event").Data(), ShouldHaveLength, 1)
-		So(data.Consume(res[4].Result[0]).Get("event.test").Data(), ShouldEqual, "DEFINE EVENT test ON test WHEN true THEN NULL")
+		So(data.Consume(res[4].Result[0]).Get("event.test").Data(), ShouldEqual, "DEFINE EVENT test ON test WHEN true THEN (CREATE test)")
 		So(data.Consume(res[4].Result[0]).Get("field").Data(), ShouldHaveLength, 1)
 		So(data.Consume(res[4].Result[0]).Get("field.test").Data(), ShouldEqual, "DEFINE FIELD test ON test")
 		So(data.Consume(res[4].Result[0]).Get("index").Data(), ShouldHaveLength, 1)

sql/event.go

@@ -46,7 +46,7 @@ func (p *parser) parseDefineEventStatement() (stmt *DefineEventStatement, err er
 		return nil, err
 	}
 
-	if stmt.Then, err = p.parseExpr(); err != nil {
+	if stmt.Then, err = p.parseMult(); err != nil {
 		return nil, err
 	}
 

sql/exprs.go

@@ -605,10 +605,7 @@ func (p *parser) parseMult() (exp *MultExpression, err error) {
 
 		var stm Expr
 
-		tok, _, exi := p.mightBe(CREATE, UPDATE, DELETE, RELATE, INSERT, UPSERT)
+		tok, _, _ := p.mightBe(CREATE, UPDATE, DELETE, RELATE, INSERT, UPSERT)
-		if !exi {
-			break
-		}
 
 		switch tok {
 		case CREATE:
@@ -633,7 +630,9 @@ func (p *parser) parseMult() (exp *MultExpression, err error) {
 
 		exp.Expr = append(exp.Expr, stm)
 
-		_, _, _ = p.mightBe(SEMICOLON)
+		if _, _, exi := p.mightBe(SEMICOLON); !exi {
+			break
+		}
 
 	}
 

sql/sql_test.go

@@ -2595,7 +2595,7 @@ func Test_Parse_Queries_Define(t *testing.T) {
 		},
 		{
 			sql: `DEFINE EVENT temp ON person WHEN $before.price < $after.price THEN`,
-			err: "Found `` but expected `expression`",
+			err: "Found `` but expected `(`",
 		},
 		{
 			sql: `DEFINE EVENT temp ON person WHEN $before.price < $after.price THEN (UPDATE $this SET increased = true)`,
@@ -2608,18 +2608,61 @@ func Test_Parse_Queries_Define(t *testing.T) {
 					Op:  LT,
 					RHS: &Param{"after.price"},
 				},
-				Then: &SubExpression{
+				Then: &MultExpression{
-					Expr: &UpdateStatement{
+					Expr: []Expr{
-						KV: "*", NS: "*", DB: "*",
+						&UpdateStatement{
-						What: Exprs{&Param{"this"}},
+							KV: "*", NS: "*", DB: "*",
-						Data: &DataExpression{[]*ItemExpression{
+							What: Exprs{&Param{"this"}},
-							{
+							Data: &DataExpression{[]*ItemExpression{
-								LHS: &Ident{"increased"},
+								{
-								Op:  EQ,
+									LHS: &Ident{"increased"},
-								RHS: true,
+									Op:  EQ,
-							},
+									RHS: true,
-						}},
+								},
-						Echo: AFTER,
+							}},
+							Echo: AFTER,
+						},
+					},
+				},
+			}}},
+		},
+		{
+			sql: `DEFINE EVENT temp ON person WHEN $before.price < $after.price THEN (UPDATE $this SET increased = true; UPDATE $this SET finished = true)`,
+			res: &Query{Statements: []Statement{&DefineEventStatement{
+				KV: "*", NS: "*", DB: "*",
+				Name: &Ident{"temp"},
+				What: Tables{&Table{"person"}},
+				When: &BinaryExpression{
+					LHS: &Param{"before.price"},
+					Op:  LT,
+					RHS: &Param{"after.price"},
+				},
+				Then: &MultExpression{
+					Expr: []Expr{
+						&UpdateStatement{
+							KV: "*", NS: "*", DB: "*",
+							What: Exprs{&Param{"this"}},
+							Data: &DataExpression{[]*ItemExpression{
+								{
+									LHS: &Ident{"increased"},
+									Op:  EQ,
+									RHS: true,
+								},
+							}},
+							Echo: AFTER,
+						},
+						&UpdateStatement{
+							KV: "*", NS: "*", DB: "*",
+							What: Exprs{&Param{"this"}},
+							Data: &DataExpression{[]*ItemExpression{
+								{
+									LHS: &Ident{"finished"},
+									Op:  EQ,
+									RHS: true,
+								},
+							}},
+							Echo: AFTER,
+						},
 					},
 				},
 			}}},

sql/string.go

@@ -741,10 +741,10 @@ func (this SubExpression) String() string {
 func (this MultExpression) String() string {
 	m := make([]string, len(this.Expr))
 	for k := range this.Expr {
-		m[k] = print("%v;", this.Expr[k])
+		m[k] = print("%v", this.Expr[k])
 	}
 	return print("(%v)",
-		strings.Join(m, " "),
+		strings.Join(m, "; "),
 	)
 }