How to delete the primary key in oracle

To delete a primary key in Oracle, you need to follow the following steps: 1. Delete the referenced foreign key constraint; 2. Delete the primary key constraint; 3. If necessary, add a new primary key constraint.

How to delete primary keys in Oracle

Deleting a primary key in an Oracle database involves the following steps:

1. Add foreign key constraints

If the primary key you want to delete has a foreign key reference, you need to first delete the foreign key constraint in the reference table. Use the following syntax:

 <code class="sql">ALTER TABLE [引用表名] DROP CONSTRAINT [外键约束名]</code>

2. Delete primary key constraints

Use the following syntax to delete the primary key constraint:

 <code class="sql">ALTER TABLE [表名] DROP CONSTRAINT [主键约束名]</code>

3. Add new primary key constraints

If needed, you can add new primary key constraints:

 <code class="sql">ALTER TABLE [表名] ADD CONSTRAINT [新主键约束名] PRIMARY KEY ([列名1], [列名2], ...)</code>

Notice:

• If there are multiple primary key columns in the table, list them all in the ALTER TABLE statement.
• If the table does not have a primary key, you can add one using the following syntax:

 <code class="sql">ALTER TABLE [表名] ADD PRIMARY KEY ([列名1], [列名2], ...)</code>

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