Remove gorm dependency from Insert()

Although this implementation was meant to work with sqlite and
postgres it was not yet tested with postgres.

kiss_orm.go

@@ -12,6 +12,7 @@ import (
 
 // Client ...
 type Client struct {
+	driver    string
 	tableName string
 	db        *gorm.DB
 }
@@ -34,6 +35,7 @@ func NewClient(
 	db.DB().SetMaxOpenConns(maxOpenConns)
 
 	return Client{
+		driver:    dbDriver,
 		db:        db,
 		tableName: tableName,
 	}, nil
@@ -252,20 +254,78 @@ func (c Client) Insert(
 	ctx context.Context,
 	records ...interface{},
 ) error {
-	if len(records) == 0 {
-		return nil
-	}
-
 	for _, record := range records {
-		r := c.db.Table(c.tableName).Create(record)
-		if r.Error != nil {
-			return r.Error
+		query, params, err := buildInsertQuery(c.tableName, record, "id")
+		if err != nil {
+			return err
+		}
+
+		switch c.driver {
+		case "postgres":
+			err = c.insertOnPostgres(ctx, record, query, params)
+		default:
+			err = c.insertWithLastInsertID(ctx, record, query, params)
 		}
 	}
 
 	return nil
 }
 
+func (c Client) insertOnPostgres(
+	ctx context.Context,
+	record interface{},
+	query string,
+	params []interface{},
+) error {
+	query = query + " RETURNING id"
+
+	rows, err := c.db.DB().QueryContext(ctx, query, params...)
+	if err != nil {
+		return err
+	}
+
+	if !rows.Next() {
+		err := fmt.Errorf("unexpected error retrieving the id from the database")
+		if rows.Err() != nil {
+			err = rows.Err()
+		}
+
+		return err
+	}
+
+	v := reflect.ValueOf(record)
+	t := v.Type()
+	info := getTagInfoWithCache(tagInfoCache, t.Elem())
+
+	fieldAddr := v.Elem().Field(info.Index["id"]).Addr()
+	return rows.Scan(fieldAddr)
+}
+
+func (c Client) insertWithLastInsertID(
+	ctx context.Context,
+	record interface{},
+	query string,
+	params []interface{},
+) error {
+	result, err := c.db.DB().ExecContext(ctx, query, params...)
+	if err != nil {
+		return err
+	}
+
+	v := reflect.ValueOf(record)
+	t := v.Type()
+	info := getTagInfoWithCache(tagInfoCache, t.Elem())
+
+	id, err := result.LastInsertId()
+	if err != nil {
+		return err
+	}
+
+	fieldAddr := v.Elem().Field(info.Index["id"]).Addr()
+	fieldAddr.Elem().Set(reflect.ValueOf(id).Convert(fieldAddr.Elem().Type()))
+	return nil
+}
+
 // Delete deletes one or more instances from the database by id
 func (c Client) Delete(
 	ctx context.Context,
@@ -304,6 +364,47 @@ func (c Client) Update(
 	return nil
 }
 
+func buildInsertQuery(
+	tableName string,
+	record interface{},
+	idFieldNames ...string,
+) (query string, params []interface{}, err error) {
+	recordMap, err := StructToMap(record)
+	if err != nil {
+		return "", nil, err
+	}
+
+	numAttrs := len(recordMap)
+	params = make([]interface{}, numAttrs)
+
+	for _, fieldName := range idFieldNames {
+		// Remove any ID field that was not set:
+		if reflect.ValueOf(recordMap[fieldName]).IsZero() {
+			delete(recordMap, fieldName)
+		}
+	}
+
+	columnNames := []string{}
+	for col := range recordMap {
+		columnNames = append(columnNames, col)
+	}
+
+	var valuesQuery []string
+	for i, col := range columnNames {
+		params[i] = recordMap[col]
+		valuesQuery = append(valuesQuery, "?")
+	}
+
+	query = fmt.Sprintf(
+		"INSERT INTO `%s` (`%s`) VALUES (%s)",
+		tableName,
+		strings.Join(columnNames, "`, `"),
+		strings.Join(valuesQuery, ", "),
+	)
+
+	return query, params, nil
+}
+
 func buildUpdateQuery(
 	tableName string,
 	record interface{},

kiss_orm_test.go

@@ -2,7 +2,6 @@ package kissorm
 
 import (
 	"context"
-	"fmt"
 	"testing"
 	"time"
 
@@ -230,6 +229,7 @@ func TestInsert(t *testing.T) {
 
 		err := c.Insert(ctx, &u)
 		assert.Equal(t, nil, err)
+		assert.NotEqual(t, 0, u.ID)
 
 		result := User{}
 		it := c.db.Raw("SELECT * FROM users WHERE id=?", u.ID)
@@ -1009,9 +1009,7 @@ func TestScanRows(t *testing.T) {
 		assert.Equal(t, nil, err)
 
 		var u map[string]interface{}
-		fmt.Println("before scan")
 		err = scanRows(rows, &u)
-		fmt.Println("after scan")
 		assert.NotEqual(t, nil, err)
 	})
 }