Confusion: How does SQLiteOpenHelper onUpgrade() behave? And together with import of an old database backup?

Question

let\'s assume I have a database table test_table with 2 columns and a corresponding create script in the SQLiteOpenHelper:

DB_VERSION = 1:
public void onCrea         


        

Answer 1

i suspect you can also create a new table with all the columns you need

CREATE TABLE new_test_table (COL_A, COL_B, COL_C,COL_D);

copy the data from the old table to the new

INSERT INTO new_test_table SELECT * FROM test_table;

drop the old table DROP TABLE test_table;

and rename the new table

ALTER TABLE new_test_table RENAME TO test_table;

so in short

public void onUpgrade(SQLiteDatabase db,int OldVersion,int NewVersion){
  db.execSQL("CREATE TABLE new_test_table (COL_A, COL_B, COL_C,COL_D);"+
             "INSERT INTO new_test_table SELECT * FROM test_table;"+
             "DROP TABLE test_table;"+
             "ALTER TABLE new_test_table RENAME TO test_table;");"
    }

that way you don't have to worry about dataloss or incremental changes