feat: support batch inserts (#22)

Author: Gustrb

create.go

@@ -3,8 +3,10 @@ package crud
 import (
 	"context"
 	stdsql "database/sql"
+	"errors"
 	"fmt"
 	"maps"
+	"reflect"
 	"slices"
 
 	"github.com/azer/crud/v2/sql"
@@ -33,6 +35,38 @@ func createAndRead(ctx context.Context, exec ExecFn, query QueryFn, record inter
 	return readLastInsert(ctx, query, record, result)
 }
 
+func bulkCreate(ctx context.Context, exec ExecFn, value any) error {
+	v := reflect.ValueOf(value)
+	if v.Kind() != reflect.Slice {
+		return errors.New("records must be a slice")
+	}
+
+	records := make([]any, 0, v.Len())
+	for i := 0; i < v.Len(); i++ {
+		records = append(records, v.Index(i).Interface())
+	}
+
+	row, columns, _, err := valuesForRecord(records[0])
+	if err != nil {
+		return err
+	}
+
+	query := sql.InsertBulkQuery(row.SQLTableName, columns, len(records))
+	values := make([]interface{}, 0, len(records)*len(columns))
+
+	for _, record := range records {
+		_, _, v, err := valuesForRecord(record)
+		if err != nil {
+			return err
+		}
+
+		values = append(values, v...)
+	}
+
+	_, err = exec(ctx, query, values...)
+	return err
+}
+
 func replaceAndGetResult(ctx context.Context, exec ExecFn, record interface{}) (stdsql.Result, error) {
 	row, columns, values, err := valuesForRecord(record)
 	if err != nil {

create_test.go

@@ -81,3 +81,43 @@ func TestCreatingRenamedTableRow(t *testing.T) {
 
 	DB.DropTables(ctx, Post{})
 }
+
+func TestCreateBulk(t *testing.T) {
+	ctx := context.Background()
+
+	DB.ResetTables(ctx, UserProfile{})
+
+	users := []UserProfile{
+		{
+			Name:  "Azer",
+			Bio:   "I like photography",
+			Email: "[email protected]",
+		},
+		{
+			Name:  "Azer2",
+			Bio:   "I like photography2",
+			Email: "[email protected]",
+		},
+		{
+			Name:  "Azer3",
+			Bio:   "I like photography3",
+			Email: "[email protected]",
+		},
+	}
+
+	err := DB.BulkCreate(ctx, users)
+	assert.Nil(t, err)
+
+	var users2 []UserProfile
+	err = DB.Read(ctx, &users2, "SELECT * FROM user_profiles")
+	assert.Nil(t, err)
+	assert.Equal(t, len(users), 3)
+
+	for i, user := range users2 {
+		assert.Equal(t, user.Name, users[i].Name)
+		assert.Equal(t, user.Bio, users[i].Bio)
+		assert.Equal(t, user.Email, users[i].Email)
+	}
+
+	DB.DropTables(ctx, UserProfile{})
+}

db.go

@@ -192,3 +192,7 @@ func Connect(driver, url string, logger *slog.Logger) (*DB, error) {
 		Logger: logger,
 	}, nil
 }
+
+func (db *DB) BulkCreate(ctx context.Context, records any) error {
+	return bulkCreate(ctx, db.Exec, records)
+}

sql/table.go

@@ -2,6 +2,7 @@ package sql
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 )
 
@@ -115,6 +116,14 @@ func InsertQuery(tableName string, columnNames []string) string {
 		tableName, strings.Join(quoteColumnNames(columnNames), ","), questionMarks)
 }
 
+func InsertBulkQuery(tableName string, columnNames []string, numRecords int) string {
+	pattern := fmt.Sprintf("(%s)", repeatComma(len(columnNames), "?"))
+	questionMarks := slices.Repeat([]string{pattern}, numRecords)
+
+	return fmt.Sprintf("INSERT INTO `%s` (%s) VALUES %s",
+		tableName, strings.Join(quoteColumnNames(columnNames), ","), strings.Join(questionMarks, ","))
+}
+
 func ReplaceQuery(tableName string, columnNames []string) string {
 	questionMarks := repeatComma(len(columnNames), "?")
 

sql/table_test.go

@@ -90,6 +90,10 @@ func TestInsertQuery(t *testing.T) {
 	assert.Equal(t, sql.InsertQuery("yolo", []string{"name", "email", "age"}), "INSERT INTO `yolo` (`name`,`email`,`age`) VALUES (?,?,?)")
 }
 
+func TestInsertBulkQuery(t *testing.T) {
+	assert.Equal(t, sql.InsertBulkQuery("yolo", []string{"name", "email", "age"}, 3), "INSERT INTO `yolo` (`name`,`email`,`age`) VALUES (?,?,?),(?,?,?),(?,?,?)")
+}
+
 func TestUpdateQuery(t *testing.T) {
 	assert.Equal(t, sql.UpdateQuery("yolo", "id", []string{"name", "email", "age"}), "UPDATE `yolo` SET `name`=?, `email`=?, `age`=? WHERE id=?")
 }