db.mysql: add null result support (fix #24130) (#24131)

vlib/db/mysql/mysql.c.v

@@ -448,6 +448,7 @@ pub fn (stmt &StmtHandle) execute(params []string) ![]Row {
 			buffer:        param.str
 			buffer_length: u32(param.len)
 			length:        0
+			is_null:       0
 		}
 		bind_params << bind
 	}
@@ -470,6 +471,7 @@ pub fn (stmt &StmtHandle) execute(params []string) ![]Row {
 	}
 	num_cols := C.mysql_num_fields(query_metadata)
 	mut length := []u32{len: num_cols}
+	mut is_null := []bool{len: num_cols}
 
 	mut binds := []C.MYSQL_BIND{}
 	for i in 0 .. num_cols {
@@ -478,6 +480,7 @@ pub fn (stmt &StmtHandle) execute(params []string) ![]Row {
 			buffer:        0
 			buffer_length: 0
 			length:        unsafe { &length[i] }
+			is_null:       unsafe { &is_null[i] }
 		}
 		binds << bind
 	}

vlib/db/mysql/mysql_orm_test.v

@@ -28,6 +28,7 @@ mut:
 	created_at time.Time @[sql_type: 'DATETIME']
 	updated_at string    @[sql_type: 'DATETIME']
 	deleted_at time.Time
+	null_date  ?time.Time @[sql_type: 'DATETIME']
 }
 
 struct TestDefaultAttribute {
@@ -179,11 +180,26 @@ fn test_mysql_orm() {
 		panic(err)
 	}
 
-	model := TestTimeType{
+	model1 := TestTimeType{
 		username:   'hitalo'
 		created_at: today
 		updated_at: today.str()
 		deleted_at: today
+		// null_date is null
+	}
+	model2 := TestTimeType{
+		username:   'tom'
+		created_at: today
+		updated_at: today.str()
+		deleted_at: today
+		null_date:  today
+	}
+	model3 := TestTimeType{
+		username:   'kitty'
+		created_at: today
+		updated_at: today.str()
+		deleted_at: today
+		// null_date is null
 	}
 
 	sql db {
@@ -191,21 +207,41 @@ fn test_mysql_orm() {
 	}!
 
 	sql db {
-		insert model into TestTimeType
+		insert model1 into TestTimeType
+		insert model2 into TestTimeType
+		insert model3 into TestTimeType
 	}!
 
 	results := sql db {
-		select from TestTimeType where username == 'hitalo'
+		select from TestTimeType
 	}!
 
 	sql db {
 		drop table TestTimeType
 	}!
 
-	assert results[0].created_at == model.created_at
+	assert results[0].created_at == model1.created_at
-	assert results[0].username == model.username
+	assert results[0].username == model1.username
-	assert results[0].updated_at == model.updated_at
+	assert results[0].updated_at == model1.updated_at
-	assert results[0].deleted_at == model.deleted_at
+	assert results[0].deleted_at == model1.deleted_at
+	assert results[0].null_date == none
+
+	assert results[1].created_at == model2.created_at
+	assert results[1].username == model2.username
+	assert results[1].updated_at == model2.updated_at
+	assert results[1].deleted_at == model2.deleted_at
+	if x := results[1].null_date {
+		// should not by `none`/`NULL`
+		assert x == model2.deleted_at
+	} else {
+		assert false
+	}
+
+	assert results[2].created_at == model3.created_at
+	assert results[2].username == model3.username
+	assert results[2].updated_at == model3.updated_at
+	assert results[2].deleted_at == model3.deleted_at
+	assert results[2].null_date == none
 
 	/** test default attribute
 	*/

vlib/db/mysql/orm.c.v

@@ -53,8 +53,9 @@ pub fn (db DB) select(config orm.SelectConfig, data orm.QueryData, where orm.Que
 		}
 	}
 
-	lengths := []u32{len: int(num_fields), init: 0}
+	mut lengths := []u32{len: int(num_fields), init: 0}
-	stmt.bind_res(fields, data_pointers, lengths, num_fields)
+	mut is_null := []bool{len: int(num_fields)}
+	stmt.bind_res(fields, data_pointers, lengths, is_null, num_fields)
 
 	mut types := config.types.clone()
 	mut field_types := []FieldType{}
@@ -112,7 +113,7 @@ pub fn (db DB) select(config orm.SelectConfig, data orm.QueryData, where orm.Que
 			stmt.fetch_column(bind, index)!
 		}
 
-		result << data_pointers_to_primitives(data_pointers, types, field_types)!
+		result << data_pointers_to_primitives(is_null, data_pointers, types, field_types)!
 	}
 
 	stmt.close()!
@@ -251,11 +252,12 @@ fn stmt_bind_primitive(mut stmt Stmt, data orm.Primitive) {
 
 // data_pointers_to_primitives returns an array of `Primitive`
 // cast from `data_pointers` using `types`.
-fn data_pointers_to_primitives(data_pointers []&u8, types []int, field_types []FieldType) ![]orm.Primitive {
+fn data_pointers_to_primitives(is_null []bool, data_pointers []&u8, types []int, field_types []FieldType) ![]orm.Primitive {
 	mut result := []orm.Primitive{}
 
 	for i, data in data_pointers {
 		mut primitive := orm.Primitive(0)
+		if !is_null[i] {
 			match types[i] {
 				orm.type_idx['i8'] {
 					primitive = *(unsafe { &i8(data) })
@@ -300,12 +302,7 @@ fn data_pointers_to_primitives(data_pointers []&u8, types []int, field_types []F
 							primitive = time.unix(timestamp)
 						}
 						.type_datetime, .type_timestamp {
-						string_time := unsafe { cstring_to_vstring(&char(data)) }
+							primitive = time.parse(unsafe { cstring_to_vstring(&char(data)) })!
-						if string_time == '' {
-							primitive = orm.Null{}
-						} else {
-							primitive = time.parse(string_time)!
-						}
 						}
 						else {}
 					}
@@ -317,6 +314,9 @@ fn data_pointers_to_primitives(data_pointers []&u8, types []int, field_types []F
 					return error('Unknown type ${types[i]}')
 				}
 			}
+		} else {
+			primitive = orm.Null{}
+		}
 		result << primitive
 	}
 

vlib/db/mysql/stmt.c.v

@@ -13,6 +13,7 @@ mut:
 	buffer        voidptr
 	buffer_length u32
 	length        &u32
+	is_null       &bool
 }
 
 const mysql_type_decimal = C.MYSQL_TYPE_DECIMAL
@@ -250,6 +251,7 @@ pub fn (mut stmt Stmt) bind_null() {
 	stmt.binds << C.MYSQL_BIND{
 		buffer_type: mysql_type_null
 		length:      0
+		is_null:     0
 	}
 }
 
@@ -261,16 +263,18 @@ pub fn (mut stmt Stmt) bind(typ int, buffer voidptr, buf_len u32) {
 		buffer:        buffer
 		buffer_length: buf_len
 		length:        0
+		is_null:       0
 	}
 }
 
 // bind_res will store one result in the statement `stmt`
-pub fn (mut stmt Stmt) bind_res(fields &C.MYSQL_FIELD, dataptr []&u8, lengths []u32, num_fields int) {
+pub fn (mut stmt Stmt) bind_res(fields &C.MYSQL_FIELD, dataptr []&u8, lengths []u32, is_null []bool, num_fields int) {
 	for i in 0 .. num_fields {
 		stmt.res << C.MYSQL_BIND{
 			buffer_type: unsafe { fields[i].type }
 			buffer:      dataptr[i]
 			length:      &lengths[i]
+			is_null:     &is_null[i]
 		}
 	}
 }