Use TEXT columns to serialize JSON structs & arrays.

arrays.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 )
 
+// Deprecated: use JSONArray instead
 type Array[T any] []T
 
 func (arr *Array[T]) Scan(value interface{}) error {

json.go

@@ -0,0 +1,88 @@
+package sqltypes
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+)
+
+type JSON[T any] struct {
+	V *T
+}
+
+func NewJSON[T any](val *T) JSON[T] {
+	return JSON[T]{V: val}
+}
+
+func (s *JSON[T]) Scan(value interface{}) error {
+	if value == nil {
+		return nil
+	}
+
+	var val T
+	switch value.(type) {
+	case []byte:
+		if err := json.Unmarshal(value.([]byte), &val); err != nil {
+			return fmt.Errorf("sqltypes: cannot unmarshal struct: %w", err)
+		}
+	case string:
+		if err := json.Unmarshal([]byte(value.(string)), &val); err != nil {
+			return fmt.Errorf("sqltypes: cannot unmarshal struct: %w", err)
+		}
+	default:
+		return fmt.Errorf("sqltypes: unknown array type %T", value)
+	}
+	*s = NewJSON(&val)
+
+	return nil
+}
+
+func (s JSON[T]) Value() (driver.Value, error) {
+	if s.V == nil {
+		return nil, nil
+	}
+	value, err := json.Marshal(s.V)
+	if err != nil {
+		return nil, err
+	}
+	return string(value), nil
+}
+
+type JSONArray[T any] struct {
+	V T
+}
+
+func NewJSONArray[T any](val *T) JSONArray[T] {
+	return JSONArray[T]{V: *val}
+}
+
+func (s *JSONArray[T]) Scan(value interface{}) error {
+	if value == nil {
+		return nil
+	}
+
+	var val T
+	switch value.(type) {
+	case []byte:
+		if err := json.Unmarshal(value.([]byte), &val); err != nil {
+			return fmt.Errorf("sqltypes: cannot unmarshal struct: %w", err)
+		}
+	case string:
+		if err := json.Unmarshal([]byte(value.(string)), &val); err != nil {
+			return fmt.Errorf("sqltypes: cannot unmarshal struct: %w", err)
+		}
+	default:
+		return fmt.Errorf("sqltypes: unknown array type %T", value)
+	}
+	*s = NewJSONArray(&val)
+
+	return nil
+}
+
+func (s JSONArray[T]) Value() (driver.Value, error) {
+	value, err := json.Marshal(s.V)
+	if err != nil {
+		return nil, err
+	}
+	return string(value), nil
+}

json_test.go

@@ -0,0 +1,99 @@
+package sqltypes
+
+import (
+	"database/sql"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type testJSON struct {
+	Foo string
+}
+
+func TestJSONValue(t *testing.T) {
+	db := connectDB(t)
+	defer db.Close()
+
+	var st JSON[testJSON]
+	st.V = &testJSON{Foo: "bar"}
+	_, err := db.Exec("INSERT INTO test_types (name, value_str) VALUES (?, ?)", "foo", st)
+	require.NoError(t, err)
+
+	var val string
+	require.NoError(t, db.QueryRow("SELECT value_str FROM test_types WHERE name = ?", "foo").Scan(&val))
+
+	require.Equal(t, `{"Foo":"bar"}`, val)
+}
+
+func TestJSONValueNil(t *testing.T) {
+	db := connectDB(t)
+	defer db.Close()
+
+	var st JSON[testJSON]
+	_, err := db.Exec("INSERT INTO test_types (name, value_str) VALUES (?, ?)", "foo", st)
+	require.NoError(t, err)
+
+	var val sql.NullString
+	require.NoError(t, db.QueryRow("SELECT value_str FROM test_types WHERE name = ?", "foo").Scan(&val))
+
+	require.False(t, val.Valid)
+}
+
+func TestJSONScan(t *testing.T) {
+	db := connectDB(t)
+	defer db.Close()
+
+	_, err := db.Exec("INSERT INTO test_types (name, value_str) VALUES (?, ?)", "foo", `{"Foo":"bar"}`)
+	require.NoError(t, err)
+
+	var st JSON[testJSON]
+	require.NoError(t, db.QueryRow("SELECT value_str FROM test_types WHERE name = ?", "foo").Scan(&st))
+
+	require.NotNil(t, st.V)
+	require.Equal(t, st.V.Foo, "bar")
+}
+
+func TestJSONScanNil(t *testing.T) {
+	db := connectDB(t)
+	defer db.Close()
+
+	_, err := db.Exec("INSERT INTO test_types (name, value_str) VALUES (?, ?)", "foo", nil)
+	require.NoError(t, err)
+
+	var st JSON[testJSON]
+	require.NoError(t, db.QueryRow("SELECT value_str FROM test_types WHERE name = ?", "foo").Scan(&st))
+
+	require.Nil(t, st.V)
+}
+
+func TestJSONSaveLoad(t *testing.T) {
+	db := connectDB(t)
+	defer db.Close()
+
+	var st JSON[testJSON]
+	st.V = &testJSON{Foo: "bar"}
+	_, err := db.Exec("INSERT INTO test_types (name, value_str) VALUES (?, ?)", "foo", st)
+	require.NoError(t, err)
+
+	var other JSON[testJSON]
+	require.NoError(t, db.QueryRow("SELECT value_str FROM test_types WHERE name = ?", "foo").Scan(&other))
+
+	require.NotNil(t, st.V)
+	require.Equal(t, st.V.Foo, "bar")
+}
+
+func TestJSONArray(t *testing.T) {
+	db := connectDB(t)
+	defer db.Close()
+
+	st := JSONArray[[]string]{V: []string{"foo", "bar"}}
+	_, err := db.Exec("INSERT INTO test_types (name, value_str) VALUES (?, ?)", "foo", st)
+	require.NoError(t, err)
+
+	var other JSON[[]string]
+	require.NoError(t, db.QueryRow("SELECT value_str FROM test_types WHERE name = ?", "foo").Scan(&other))
+
+	require.NotNil(t, st.V)
+	require.Len(t, st.V, 2)
+}

struct.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 )
 
+// Deprecated: use JSON instead
 type Struct[T any] struct {
 	V *T
 }