lobilonestar.blogg.se

In other words, the purpose of AUTOINCREMENT is to prevent the reuse of ROWIDs from previously deleted rows. Performance improvement: If you have an additional UNIQUE Key, then add it to the WHERE to get only one row. If the AUTOINCREMENT keyword appears after INTEGER PRIMARY KEY, that changes the automatic ROWID assignment algorithm to prevent the reuse of ROWIDs over the lifetime of the database. SQLite Error 1: AUTOINCREMENT is only allowed on an INTEGER PRIMARY KEY. How do I create an AUTOINCREMENT field What datatypes does SQLite support SQLite lets me insert a string into a database column of type integer Why doesn't SQLite allow me to use '0' and '0. This is true regardless of whether or not the AUTOINCREMENT keyword is used. In SQLite, a column with type INTEGER PRIMARY KEY is an alias for the ROWID(except in WITHOUT ROWIDtables) which is always a 64-bit signed integer. On an INSERT, if the ROWID or INTEGER PRIMARY KEY column is not explicitly given a value, then it will be filled automatically with an unused integer, usually one more than the largest ROWID currently in use. Summary The AUTOINCREMENT keyword imposes extra CPU, memory, disk space, It is usually not needed. In SQLite, a column with type INTEGER PRIMARY KEY is an alias for the ROWID (except in WITHOUT ROWID tables) which is always a 64-bit signed integer. INSERT INTO PaymentInformation (NAME, Start, End) VALUES ('Tina','','') WHERE NOT EXISTS ( SELECT FROM PaymentInformation WHERE name 'Tina' AND durationstart '' ) Is this how it should be done It shouldn't insert if Tina is already in the table with a Start day of. The AUTOINCREMENT keyword imposes extra CPU, memory, disk space, and disk I/O overhead and should be avoided if not strictly needed. It can be applied to a field when creating a table. The AUTOINCREMENT keyword can be used with INTEGER PRIMARY KEY field only. You can create a UNIQUE INDEX which has essentially the same effect as a PRIMARY KEY.

The SQLite AUTOINCREMENT is a keyword used for auto incrementing a value of a field in the table. Summary: in this tutorial, you will learn about SQLite AUTOINCREMENT column attribute and when to use it in your table.