![]() The original table will still exist in the database called old_products. You can drop the old_productstable once you have verified that your products table and data are as expected. In SQLite, you can not use the ALTER TABLE statement to drop a unique constraint. The syntax to drop a unique constraint from a table in SQLite is: PRAGMA foreign_keys=off Instead, you must create a new table with the unique constraint removed and copy the data into this new table. PRAGMA foreign_keys=on table_name The name of the table to modify. This is the table that you wish to remove the unique constraint from. old_table The name of the original table. It will be left behind after you have created the new table with the unique constraint removed. Let's look at an example of how to remove a unique constraint from an existing table in SQLite. So say, we already have a suppliers table with the following definition: CREATE TABLE suppliers Sqlitestudio advanced check constraints how to# INSERT INTO suppliers SELECT * FROM old_suppliers We could run the following commands: PRAGMA foreign_keys=off ĪLTER TABLE suppliers RENAME TO old_suppliers ( supplier_id INTEGER PRIMARY KEY AUTOINCREMENT,ĬONSTRAINT supplier_name_unique UNIQUE (supplier_name)Īnd we wanted to drop the unique constraint from the suppliers table. In this example, we've dropped the unique constraint on the existing suppliers table. You can drop the old_suppliers table once you have verified that your suppliers table and data are as expected.In this example, foreign keys are used for the type of connection data in connections.type The original table will still exist in the database called old_suppliers. To avoid the need to continually write out the words Phone, Fax, or Cell in the connection data, there is a shortcut for each category. This opens another dialog in which you select the table ( types To make these shortcuts binding for the entries in connections.typeĪs a foreign key. Section, you can make some additional fine adjustments if needed. Next, populate the tables with sample data. ![]()
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