Sqlite – How to get a list of column names on Sqlite3 database

sqlite

I want to migrate my iPhone app to a new database version. Since I don't have some version saved, I need to check if certain column names exist.

This Stackoverflow entry suggests doing the select

SELECT sql FROM sqlite_master
WHERE tbl_name = 'table_name' AND type = 'table'

and parse the result.

Is that the common way? Alternatives?

PRAGMA table_info(table_name);

will get you a list of all the column names.

There are a few steps to see the tables in an SQLite database:

Say you have a table and need to rename "colb" to "col_b":

First you rename the old table:

ALTER TABLE orig_table_name RENAME TO tmp_table_name;

Then create the new table, based on the old table but with the updated column name:

CREATE TABLE orig_table_name (
  col_a INT
, col_b INT
);

Then copy the contents across from the original table.

INSERT INTO orig_table_name(col_a, col_b)
SELECT col_a, colb
FROM tmp_table_name;

Lastly, drop the old table.

DROP TABLE tmp_table_name;

Wrapping all this in a BEGIN TRANSACTION; and COMMIT; is also probably a good idea.