Android – How to delete column from sqlite table in android

androidsqlite

I tried deleting a column by using the following

openDB.execSQL("ALTER TABLE favs" + " DROP COLUMN favsCount");

LogCat gives the following message:

11-07 21:18:29.238: ERROR/Database(13952): Failure 1 (near "DROP": syntax error) on 0x34e550 when preparing 'ALTER TABLE favs DROP COLUMN favsCount'.

Is it not possible to delete fields in sqlite for Android?

Best Answer

Sorry, SQLite doesn't support DROP COLUMN:

(11) How do I add or delete columns from an existing table in SQLite.

SQLite has limited ALTER TABLE support that you can use to add a column to the end of a table or to change the name of a table. [...]

For example, suppose you have a table named "t1" with columns names "a", "b", and "c" and that you want to delete column "c" from this table. The following steps illustrate how this could be done:
BEGIN TRANSACTION;
CREATE TEMPORARY TABLE t1_backup(a,b);
INSERT INTO t1_backup SELECT a,b FROM t1;
DROP TABLE t1;
CREATE TABLE t1(a,b);
INSERT INTO t1 SELECT a,b FROM t1_backup;
DROP TABLE t1_backup;
COMMIT;

So basically, you have to use the "copy, drop table, create new table, copy back" technique to remove a column.

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Kotlin Syntax

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Best Answer

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