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SQLite delete column in one table 31 七月, 2007

Posted by leterboy in Embedding System.
8 comments

Data from http://www.sqlite.org/faq.html#q11

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. If you what make more complex changes the structure of a table, you will have to recreate the table. You can save existing data to a temporary table, drop the old table, create the new table, then copy the data back in from the temporary 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;

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