Notice that if you assign another integer type such as BIGINT and UNSIGNED INT to the primary key column, this column will not be an alias for the rowid column.īecause the rowid table organizes its data as a B-tree, querying and sorting data of a rowid table are very fast. If a table has the primary key that consists of one column, and that column is defined as INTEGER then this primary key column becomes an alias for the rowid column. Tables that have rowid columns are called rowid tables. The rowid column is a key that uniquely identifies the rows in the table. When you create a table without specifying the WITHOUT ROWID option, SQLite adds an implicit column called rowid that stores 64-bit signed integer. However, to make the current version of SQLite compatible with the earlier version, SQLite allows the primary key column to contain NULL values. It means that the primary key column has an implicit NOT NULL constraint. In SQL standard, the primary key column must not contain NULL values.
SQLITE FOREIGN KEY CODE
) Code language: SQL (Structured Query Language) ( sql ) Second, in case primary key consists of two or more columns, you use the PRIMARY KEY table constraint to define the primary as shown in the following statement. SQLite allows you to define primary key in two ways:įirst, if the primary key has only one column, you use the PRIMARY KEY column constraint to define the primary key as follows: CREATE TABLE table_name( Each table has one and only one primary key. Introduction to SQLite primary keyĪ primary key is a column or group of columns used to identify the uniqueness of rows in a table.
SQLITE FOREIGN KEY HOW TO
In the data editor, you can now select several values and navigate to the related data.Īlso, you can watch the Navigate by foreign keys video at for another example.Summary: in this tutorial, you will learn how to use SQLite PRIMARY KEY constraint to define a primary key for a table. Referencing Rows: rows that are referencing the current object.Īll Related Rows: both referenced and referencing rows. Referenced Rows: rows that are referenced by the current object. In the Go To submenu, you can select to which type of related rows you want to navigate. Right-click a column in a table and select Go To. For a primary key, for example, the template is index template generates the following name for the not unique index: persons_FirstName_LastName_index. When you create indexes, and primary and foreign key constraints, their default names are generated according to corresponding templates. Productivity tips Modify templates for generated index and key names In the Target Name field, specify the name of the column in the target table. In the Column Name field, specify the name of the column in the child table.
In the Columns pane, click the Add button ( ). In the Target Table pane, specify the name of the target table. Right-click a child table and select New | Foreign Key.
SQLITE FOREIGN KEY WINDOWS
In the Database tool window ( View | Tool Windows | Database), expand the data source tree until the node of a child table. In the following example, activity.activity_id is a primary key, while visitor.activity_id is a foreign key.
If your database contains explicit foreign key relationships, P圜harm automatically uses them in auto-completion, data navigation, and diagrams. The table that contains a candidate key is a referenced or target table. The table that contains a foreign key is a child table. FOREIGN KEY (activity_id) REFERENCES activity(activity_id)
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