A unique index will allow a NULL a primary key constraint wont. You can implement it with your way - to check next available ID every time, because you have multiple mobile devices, and you have objects at API side with ID's 1, 2, 3, 4, 5, you can in the same moment, try to create new object at TWO DIFFERENT mobile devices with ID 6, which would lead conflict at API side later on. UNIQUE INDEX alone doesnt have the same effect as PRIMARY KEY. Suppose we want to create a new table named 'customers' with the following columns: id, name, email, and address. Example 1: Creating a new table with an autoincrement column. When your object has been synchronized with API, ID should match API object ID. Let's take a few examples to explore the use of autoincrement in SQLite. 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. ![]() When your object is local only (hasn't been synchronized with API yet), it should have only LocalID filled, and ID = 0. Summary The AUTOINCREMENT keyword imposes extra CPU, memory, disk space, and disk I/O overhead and should be avoided if not strictly needed. LocalID is used only at mobile app side, and it's not used by API side. YourModel table with two ID's colum - LocalID (any autoincrement/autogenerated/guid ID, and it would be PRIMARY KEY at mobile side) + COMPLETELLY UNIQUE ID column (based on objects ID's at API side). YourModelUniqueApi1:1 table + YourModelTempLocal table ( WITHOUT ROWID tables are the exception. ![]() The keyword AUTOINCREMENT can be used with INTEGER field only. Lol, that's standard "problem" with multiple non-synchronized DB.įirst of all - if you want to be able to create any unique objects at API, as well as at multiple mobile devices side, you need to have: In SQLite, table rows normally have a 64-bit signed integer ROWID which is unique among all rows in the same table. SQLite Error 1: AUTOINCREMENT is only allowed on an INTEGER PRIMARY KEY. You can leave the column out of the insert statement (implying a null) or you can insert an explicit NULL into the column to cause it to autoincrement. SQLite AUTOINCREMENT is a keyword used for auto incrementing a value of a field in the.
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