When used in INTEGER PRIMARY KEY AUTOINCREMENT, a slightly different algorithm for Id creation is used. The main purpose of using attribute AUTOINCREMENT is to prevent SQLite to reuse a value that has not been used or a value from the previously deleted row. How can you use the auto increment key of one table into another table to not get a new ID in the second table and use the ID of the first one (Python. Here is the syntax to define ID attribute as a primary key in a COMPANY table. 4 Answers Sorted by: 46 In SQLite, INTEGER PRIMARY KEY column is auto-incremented. Generally, the auto increment property in SQLite can only work with numeric data types and its very useful to use with primary key constraints because primary key will always allow only unique values.
Note: You would use these concepts while creating database tables. If a table has a primary key defined on any field(s), then you cannot have two records having the same value of that field(s). When multiple fields are used as a primary key, they are called a composite key. A primary key column cannot have NULL values.Ī table can have only one primary key, which may consist of single or multiple fields. Some may be left out in special cases where a rowid is already assigned but the insert fails due to constraints.
#SQLITE AUTOINCREMENT ID PYTHON HOW TO#
Note that lastrowid returns None when you insert more than one row at a time with executemany: cursor.A primary key is a field in a table which uniquely identifies the each rows/records in a database table. Learn how to set-up and use a primary key from sqlite for python programmingPatreon. It would take AUTOINCREMENT to guarantee that SQLite does not re-use the rowids of deleted records and even that does not guarantee that the rowids assigned are contigous.
If two people are inserting at the same time, as long as they are using different cursors, cursor.lastrowid will return the id for the last row that cursor inserted: cursor.execute('INSERT INTO foo (username,password) VALUES (?,?)',Ĭursor2.execute('INSERT INTO foo (username,password) VALUES (?,?)',Ĭursor.execute('INSERT INTO foo (id,username,password) VALUES (?,?,?)', You could use cursor.lastrowid (see "Optional DB API Extensions"): connection=nnect(':memory:')Ĭursor.execute('''CREATE TABLE foo (id integer primary key autoincrement ,Ĭursor.execute('INSERT INTO foo (username,password) VALUES (?,?)',
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