DATA DEFINITION LANGUAGE


What is Data Definition Language?

Source: DataSunrise

Data Definition Language (DDL) uses a set of preset commands and a specific syntax to construct and modify objects' structures within databases. The tables, sequences, locations, aliases, schemas, and indexes that are part of this database are among them.

Storage groups, various structures, and other objects in a database can be defined using commands in the standardized language DDL. Tables, indexes, and stogroups are examples of database objects that can be created, modified, or deleted using DDL commands. Any language that specifies data can also be referred to as DDL in a general sense.

Databases, aliases, locations, indexes, tables, and sequences can all be created and deleted using DDL statements written in Structured Query Language (SQL). Statements to modify these objects and add or remove certain table restrictions are also included.

Examples of these statements are as follows:

  • UNIQUE
  • PRIMARY
  • FOREIGN KEY
  • CHECK

Common DDL commands include:

  • CREATE: To create new tables or databases.
  • ALTER: To modify existing database structures.
  • DROP: To delete tables or databases.
  • TRUNCATE: To remove all records from a table without deleting the table itself.
DDL commands are essential for setting up the schema of a database and managing its structural elements.

Comments

Post a Comment

Popular posts from this blog

EMBEDDED DATA MANIPULATION LANGUAGE

Image
 WHAT IS EMBEDDED DATA MANIPULATION LANGUAGE? Source: DataFlair Embedded Data Manipulation Language (EDML) refers to the integration of data manipulation commands within a host programming language, allowing developers to execute database operations directly within their application code. This approach enables seamless interaction with databases while leveraging the features of the host language, such as control structures and data types. Commonly used in environments like Java, C#, or Python, EDML enhances performance and flexibility by embedding SQL commands in the application logic. In terms of implementation, EDML typically involves: Syntax: SQL statements are embedded directly in the code, often within specific functions or methods. For example, using prepared statements in Java can improve security and performance. Access Methods: Developers use various libraries and frameworks (like JDBC for Java or Entity Framework for C#) to facilitate the integration of SQL within the hos...
Read more

INTERACTIVE DATA MANIPULATION LANGUAGE

Image
What is Data Manipulation Language? Source: ShutterShock Data can be added, removed, modified, and retrieved from databases using Data Manipulation Language (DML), a subset of SQL. Users may manage and alter data within database tables with the use of important commands like SELECT, INSERT, UPDATE, and DELETE.  
Read more