But the seq value differs as there are multiple columns in the key. So, the multiple column key results in multiple rows in the output where id is same as this is actually one key. So if you take the next example - sqlite> CREATE TABLE Test2 (first INTEGER, second INTEGER, FOREIGN KEY (first, second) REFERENCES A(a, b) ON DELETE CASCADE) 18.1k 6 6 gold badges 46 46 silver badges 42 42 bronze badges. You can see the id fields value are 0 and 1 respectively but the seq values are all 0.Īs you may know sqlite allows multiple column names in foreign key statement. More information you can find on sqlite foreign keys doc. You can see there are two foreign keys in table Test and so there are two entries shown in PRAGMA foreign_key_list() output. I know the table Test look like a nightmare, but just ignore the horrible schema for a moment. Id seq table from to on_update on_delete match In the following example, two tables customers and customeroffers will be created, the cusotmersoffers table will contain the foreign key constraint fkcustomerid to enforce the relationships between rows of tables. A foreign key is a primary key from another table. The first thing we should do is to enable foreign key support (if it hasn’t already been done).
This article provides an example of creating a foreign key when creating a table in SQLite. Take below example executed in sqlite3 cli with header and column option on - CREATE TABLE Test (first INTEGER, second INTEGER, FOREIGN KEY (first) REFERENCES A(a) ON DELETE CASCADE, FOREIGN KEY (second) REFERENCES B(x) ON DELETE CASCADE) A SQLite FOREIGN KEY is a constraint used to link two tables. When you create a table in SQLite, you can also create a foreign key in order to establish a relationship with another table. XDatabase is a simple unified library to interact with SQLite, MySQL.
So, in the output you got the first two 0s are for id and seq. For example, when you create a form, you can add a button to the form - perhaps to. Hence, the deferforeignkeys pragma must be separately enabled for each transaction. The deferforeignkeys pragma is automatically switched off at each COMMIT or ROLLBACK. Id, seq, table, from, to, on_update, on_delete, match The deferforeignkeys pragma defaults to OFF so that foreign key constraints are only deferred if they are created as 'DEFERRABLE INITIALLY DEFERRED'. The output of PRAGMA foreign_key_list() consists of following columns in order.
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