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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?
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DB Browser for SQLite allows you to add or drop columns. In the main view, tab Database Structure , click on the table name. A button Modify Table gets enabled, which opens a new window where you can select the column/field and remove it.
Right-click the column you want to delete and choose Delete Column from the shortcut menu. If the column participates in a relationship (FOREIGN KEY or PRIMARY KEY), a message prompts you to confirm the deletion of the selected columns and their relationships. Choose Yes.
sqlite> DELETE FROM table_name; Following is the basic syntax of DROP TABLE. sqlite> DROP TABLE table_name; If you are using DELETE TABLE command to delete all the records, it is recommended to use VACUUM command to clear unused space.
The syntax to ADD A COLUMN in a table in SQLite (using the ALTER TABLE statement) is: ALTER TABLE table_name ADD new_column_name column_definition; table_name.
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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as mu is too short says Sqlite doesn't allow to do an alter table to delete a column. here you can see the alter syntax definition
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