DDL (Data Definition Language) is generally used for performing tasks like creating the structure of the relations and deleting relations in a database.

Explanation:

DDL stands for Data Definition Language, and it is a set of SQL commands used for defining the database schema. It allows users to create, modify, and delete database objects such as tables, views, indexes, and sequences. DDL statements are used to define the structure of the database and its objects.

Creating the Structure of Relations:

One of the main tasks performed by DDL is creating the structure of relations, i.e., creating tables. Tables are used to store data in a structured manner. With DDL, you can specify the name of the table, define the columns and their data types, set constraints, and define any indexes or keys necessary for the table.

For example, to create a table called "Employees" with columns such as "EmployeeID," "FirstName," and "LastName," you would use a DDL statement like:

```
CREATE TABLE Employees (
EmployeeID INT PRIMARY KEY,
FirstName VARCHAR(50),
LastName VARCHAR(50)
);
```

This statement creates a table named "Employees" with three columns: "EmployeeID" of type INT, "FirstName" of type VARCHAR(50), and "LastName" of type VARCHAR(50).

Deleting Relations:

DDL is also used for deleting relations, i.e., dropping tables from the database. When a table is no longer needed or if it needs to be recreated with different structure, the DROP TABLE statement can be used. This statement removes the specified table and all its associated data.

For example, to delete the "Employees" table created earlier, you would use the following DDL statement:

```
DROP TABLE Employees;
```

This statement removes the "Employees" table and all its data from the database.

In summary, DDL is used for creating the structure of relations (tables) and deleting relations (dropping tables) in a database. It is an essential part of database management and allows users to define and modify the structure of the database schema.