In the window which will open select the column you want to make the foreign key and scroll to your right you will find a column written foreign key and easily select the table yo are referencing to plus the column. A complete SQL database with multiple tables, indices, triggers, and views, is contained in a single disk file. Open your database, right click your table, select modify database. It reads and writes directly to ordinary disk files. SQLite is different from other SQL databases because unlike most other SQL databases, SQLite does not have a separate server process. In other words, "SQLite is an open source, zero-configuration, self-contained, stand alone, transaction relational database engine designed to be embedded into an application". SQLite is free to use for any purpose commercial or private. Our SQLite Tutorial includes all topics of SQLite such as SQLite with history, features, advantages, installation, commands, syntax, datatypes, operators, expressions, databases, table, crud operations, clauses, like, glob, limit, and clause, advance sqlite etc. It is self-contained, serverless, zero configuration and transactional SQL database engine. SQLite is embedded relational database management system. Our SQLite Tutorial is designed for beginners and professionals both. Now, let's demonstrate how the ON DELETE SET NULL works.SQLite Tutorial provides basic and advanced concepts of SQLite. In this example, we've created a foreign key (with set null on delete) called fk_departments that references the departments table based on the department_id field. INSERT INTO employees SELECT * FROM _employees_old Now, let's add a foreign key with ON DELETE SET NULL to the employees table: PRAGMA foreign_keys=off ĪLTER TABLE employees RENAME TO _employees_old Fix another bug after following a foreign key value, broken somewhere in issue. INSERT INTO employees VALUES (10001, 'Anderson', 'Dave', 999) Creating a trigger Creating a scheduled event The Data tab Running SQL. INSERT INTO employees VALUES (10000, 'Smith', 'John', 30) INSERT INTO departments VALUES (999, 'Sales') It enforces referential integrity within SQLite database. INSERT INTO departments VALUES (30, 'HR') SQLite Foreign Key is used to specify that values in one table also appear in another table. Next, let's add some data to these tables: To show how this works, first define two database tables that don’t have any foreign keys: - salespeople - CREATE TABLE salespeople ( id INTEGER PRIMARY KEY, firstname TEXT NOT NULL, lastname TEXT NOT NULL, commissionrate REAL NOT NULL ) - customers - CREATE TABLE customers ( id INTEGER PRIMARY KEY. INSERT INTO table1 SELECT * FROM _table1_old įirst, let's start by creating our 2 tables ( departments and employees): The syntax to add a foreign key with "set null on delete" to an existing table in SQLite is: PRAGMA foreign_keys=off ĪLTER TABLE table1 RENAME TO _table1_old Instead you will need to rename the table, create a new table with the foreign key, and then copy the data into the new table. You can not use the ALTER TABLE statement to add a foreign key with "set null on delete" in SQLite. How to Add a Foreign Key with "Set NULL on Delete" to an Existing Table Then we've created a foreign key called fk_departments on the employees table that references the departments table based on the department_id field.īecause of the ON DELETE SET NULL, when a record in the departments table is deleted, all corresponding records in the employees table will have the department_id set to NULL. In this example, we've created a primary key on the departments table that consists of only one field - the department_id field. ( employee_id INTEGER PRIMARY KEY AUTOINCREMENT, ( department_id INTEGER PRIMARY KEY AUTOINCREMENT, Let's look at an example of how to create a foreign key with "set null on delete" using the CREATE TABLE statement in SQLite. REFERENCES parent_table (column1, column2. The syntax for creating a foreign key with "set null on delete" using a CREATE TABLE statement in SQLite is: CREATE TABLE table_nameįOREIGN KEY (column1, column2. How to Create a Foreign Key with "Set Null on Delete" using a CREATE TABLE statement Syntax
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