default constraint in MySQL

The DEFAULT keyword in MySQL is a database CONSTRAINT applied when inserting new records into a table.  When inserting a record in a table, if the value of any column is not provided, the default value is used. 

* For most of the data types, DEFAULT value is NULL;
* For numeric data types, the default is 0;

We can explicitly set the DEFAULT value for a column using the MySQL DEFAULT constraint.

<pre><code>
  CREATE TABLE Employee (
    id int NOT NULL,
    name varchar(255) default "Noname" NOT NULL
  );
</code></pre>
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