KQLite/com.kqlite.migration/AlterTable

AlterTable

Provides a set of functions to perform ALTER TABLE operations on a database table.

This interface defines the contract for modifying the structure of an existing table, such as renaming the table, renaming a column, adding a new column, or dropping an existing column. Implementations of this interface are responsible for generating and executing the appropriate SQL ALTER TABLE statements.

Example

class MigrationV12 : KQLiteMigration(1, 2) {
    override fun migrate(database: KQLiteDatabase) {
         // It is already in EXCLUSIVE TRANSACTION
         // Fetching schema object
         val schema = database.schema()

         // RENAME TABLE: 'users_old' to 'users'
         // Assuming the `Users` table name has been changed to 'users'
         // ALTER TABLE `users_old` RENAME TO `users`;
         schema
             .alterTable(Users)
             .renameTable("users_old", Users.tableName)



         // RENAME COLUMN: 'first_name' to 'fullName'
         // Assuming the `Users` table object now has a `fullName` column definition
         // with updated column name as 'fullName'.
         // ALTER TABLE `Users` RENAME COLUMN `first_name` TO `fullName`;
         schema
             .alterTable(Users)
             .renameColumn("first_name", Users.fullName)



         // ADD COLUMN: 'email' to the 'Users' table.
         // Assuming the `Users` table object now includes an `email` column definition.
         // ALTER TABLE `Users` ADD COLUMN `email` TEXT NOT NULL DEFAULT '';
         schema
             .alterTable(Users)
             .addColumn(Users.email)



         // DROP COLUMN: 'age' from the 'Users' table.
         // Assuming the `age` property has been removed from the `Users` table object.
         // ALTER TABLE `Users` DROP COLUMN `age`;
             .alterTable(Users)
             .dropColumn("age")
    }
}