Add: delete tag on file

pkg/database/error.go

@@ -0,0 +1,10 @@
+package database
+
+import (
+	"errors"
+)
+
+var (
+	ErrNotFound = errors.New("object not found")
+	ErrTagNotFound = errors.New("tag not found")
+)

pkg/database/method_tag_and_file.go

@@ -1,8 +1,14 @@
 package database
 
 func (database *Database) PutTagOnFile(tagID, fileID, userID int64) error {
-	_, err := database.stmt.putTagOnFile.Exec(tagID, fileID, userID)
-	return err
+	result, err := database.stmt.putTagOnFile.Exec(tagID, fileID, userID)
+	if err != nil {
+		return err
+	}
+	if rows, _ := result.RowsAffected(); rows == 0 {
+		return ErrTagNotFound
+	}
+	return nil
 }
 
 func (database *Database) GetTagsOnFile(fileID int64) ([]*Tag, error) {
@@ -23,3 +29,14 @@ func (database *Database) GetTagsOnFile(fileID int64) ([]*Tag, error) {
 	}
 	return tags, nil
 }
+
+func (database *Database) DeleteTagOnFile(tagID, fileID int64) error {
+	result, err := database.stmt.deleteTagOnFile.Exec(tagID, fileID)
+	if err != nil {
+		return err
+	}
+	if rows, _ := result.RowsAffected(); rows == 0 {
+		return ErrTagNotFound
+	}
+	return nil
+}

pkg/database/sql_stmt.go

@@ -198,6 +198,8 @@ FROM file_has_tag
 JOIN tags ON file_has_tag.tag_id = tags.id
 WHERE file_has_tag.file_id = ?;`
 
+var deleteTagOnFileQuery = `DELETE FROM file_has_tag WHERE tag_id = ? AND file_id = ?;`
+
 type Stmt struct {
 	initFilesTable     *sql.Stmt
 	initFoldersTable   *sql.Stmt
@@ -236,6 +238,7 @@ type Stmt struct {
 	updateTag          *sql.Stmt
 	putTagOnFile       *sql.Stmt
 	getTagsOnFile      *sql.Stmt
+	deleteTagOnFile    *sql.Stmt
 }
 
 func NewPreparedStatement(sqlConn *sql.DB) (*Stmt, error) {
@@ -528,5 +531,11 @@ func NewPreparedStatement(sqlConn *sql.DB) (*Stmt, error) {
 		return nil, err
 	}
 
+	// init deleteTagOnFile
+	stmt.deleteTagOnFile, err = sqlConn.Prepare(deleteTagOnFileQuery)
+	if err != nil {
+		return nil, err
+	}
+
 	return stmt, err
 }