What is Database Language ? Its Types | Data Type SQL

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Database languages are used to read, update and store data in a database. There are several such languages that can be used for this purpose; one of them is SQL (Structured Query Language). Databases serve an important function for many individuals and companies, providing a practical way to organize and store information on a computer. In programming, developers use database languages to maintain and monitor an electronic database and its management system. These languages perform a variety of critical tasks that help a database management system function correctly. In this article, we define database languages, explain the different types of languages and provide a list of some common database languages and their uses.

  • A DBMS has appropriate languages and interfaces to express database queries and updates.
  • Database languages can be used to read, store and update the data in the database.

Types of Database Language

DBMS languages

1. Data Definition Language

Data definition language (DDL) creates the framework of the database by specifying the database schema, which is the structure that represents the organization of data. Its common uses include the creation and alteration of tables, files, indexes and columns within the database. This language also allows users to rename or drop the existing database or its components. Here’s a list of DDL statements:

  • It is used to create schema, tables, indexes, constraints, etc. in the database.
  • Using the DDL statements, you can create the skeleton of the database.
  • Data definition language is used to store the information of metadata like the number of tables and schemas, their names, indexes, columns in each table, constraints, etc.

Here are some tasks that come under DDL:

  • Create: It is used to create objects in the database.
  • Alter: It is used to alter the structure of the database.
  • Drop: It is used to delete objects from the database.
  • Truncate: It is used to remove all records from a table.
  • Rename: It is used to rename an object.
  • Comment: It is used to comment on the data dictionary.

These commands are used to update the database schema that’s why they come under Data definition language.

2. Data Manipulation Language

DML stands for Data Manipulation Language. It is used for accessing and manipulating data in a database. It handles user requests. Data manipulation language (DML) provides operations that handle user requests, offering a way to access and manipulate the data that users store within a database. Its common functions include inserting, updating and retrieving data from the database. Here’s a list of DML statements:

  • Select: It is used to retrieve data from a database.
  • Insert: It is used to insert data into a table.
  • Update: It is used to update existing data within a table.
  • Delete: It is used to delete all records from a table.
  • Merge: It performs UPSERT operation, i.e., insert or update operations.
  • Call: It is used to call a structured query language or a Java subprogram.
  • Explain Plan: It has the parameter of explaining data.
  • Lock Table: It controls concurrency.

3. Data Control Language

Data control language (DCL) controls access to the data that users store within a database. Essentially, this language controls the rights and permissions of the database system. The DCL execution is transactional. It also has rollback parameters. It allows users to grant or revoke privileges to the database. Here’s a list of DCL statements:

Here are some tasks that come under DCL:

  • Grant: It is used to give user access privileges to a database.
  • Revoke: It is used to take back permissions from the user.

There are the following operations which have the authorization of Revoke:


4. Transaction Control Language

TCL is used to run the changes made by the DML statement. TCL can be grouped into a logical transaction. Transaction control language (TCL) manages the transactions within a database. Transactions group a set of related tasks into a single, executable task. All the tasks must succeed in order for the transaction to work. Here’s a list of TCL statements:

Here are some tasks that come under TCL:

  • Commit: It is used to save the transaction on the database.
  • Rollback: It is used to restore the database to original since the last Commit.

Examples of database languages

Here are six examples of database languages and how to use them:


SQL, which stands for Structured Query Language, is one of the most well-known and longest-running database languages. It features both data definition and data manipulation languages and allows you to write queries in a database. Specifically, SQL provides a way for you to extract and manage data in a relational database management system. This type of DBMS organizes data into groups called relations. Because most relational databases use SQL as the database language, many jobs in the IT industry may require their employees to have an understanding of it.


XQuery is a database language that allows you to extract and manipulate data in XML formats, which is a way to share data on the internet. You can use XQuery to access and retrieve any data source in an XML format. With XQuery, you can generate reports on data within an XML database, search text documents on the web for data and extract data for use online.


OQL, which stands for Object Query Language, is the standard language for object-oriented databases, which represent data as variables, functions or data structures. These databases are popular with companies that want to store large amounts of complex data. Much like SQL does in relational databases, OQL gives you the option to perform queries and retrieve data in object databases.


The SQL/XML language is a combination of SQL and XQuery that supports the manipulation and storage of XML data in a database that works with SQL. It enables applications to perform SQL statements on XML data and vice versa. It’s helpful when you want to extract content from an XML document or if you want to ensure compatibility with future optimizations or systems that may only support XML.


GraphQL is an open-source language that works with APIs, which are interfaces that allow users to interact with data. It provides a way to define the structure of data and how the system returns information in order to prevent the release of excessive amounts of data. It’s helpful when you want to extract data from multiple APIs, aggregate data from different sources or specify the data efficiently.


LINQ, or Language Integrated Query, is a language that extracts and processes data from XML documents, relational databases and other third-party sources. With LINQ, you can access data through various sources without having to use a separate database language for each one. This ensures consistency among queries for objects, relational databases and XML, allowing you to filter, order and group operations.


A DBMS interface is the abstraction of a piece of functionality of a DBMS. It usually refers to the communication boundary between the DBMS and clients or to the abstraction provided by a component within a DBMS. A DBMS interface hides the implementation of the functionality of the component it encapsulates.

A database management system or DBMS is an software application which is used to define, manipulate, retrieve, and manage data information in a database. Data types are classified to identify possible values stored in the column.

  • SQL Datatype is used to define the values that a column can contain.
  • Every column is required to have a name and data type in the database table.

A database data type refers to the format of data storage that can hold a distinct type or range of values. When computer programs store data in variables, each variable must be designated a distinct data type. Some common data types are as follows: integers, characters, strings, floating point numbers and arrays.

Datatype of SQL:

sql data types

1. Binary Datatypes

There are Three types of binary Datatypes which are given below:

Data TypeDescription
cIt has a maximum length of 8000 bytes. It contains fixed-length binary data.
varbinaryIt has a maximum length of 8000 bytes. It contains variable-length binary data.
imageIt has a maximum length of 2,147,483,647 bytes. It contains variable-length binary data.

2. Approximate Numeric Datatype :

The subtypes are given below:

Data typeFromToDescription
float-1.79E + 3081.79E + 308It is used to specify a floating-point value e.g. 6.2, 2.9 etc.
real-3.40e + 383.40E + 38It specifies a single precision floating point number

3. Exact Numeric Datatype

The subtypes are given below:

Data typeDescription
intIt is used to specify an integer value.
smallintIt is used to specify small integer value.
bitIt has the number of bits to store.
decimalIt specifies a numeric value that can have a decimal number.
numericIt is used to specify a numeric value.

4. Character String Datatype

The subtypes are given below:Competitive questions on Structures in HindiKeep Watching

Data typeDescription
charIt has a maximum length of 8000 characters. It contains Fixed-length non-unicode characters.
varcharIt has a maximum length of 8000 characters. It contains variable-length non-unicode characters.
textIt has a maximum length of 2,147,483,647 characters. It contains variable-length non-unicode characters.

5. Date and time Datatypes

The subtypes are given below:

dateIt is used to store the year, month, and days value.
timeIt is used to store the hour, minute, and second values.
timestampIt stores the year, month, day, hour, minute, and the second value.

6. SQL Miscellaneous Data Types

CLOBCharacter large objects that can hold up to 2GB
BLOBFor binary large objects
XMLfor storing XML data
JSONfor storing JSON data

7. SQL Unicode Character and String Data Types

NCHARFixed length with maximum length of 4,000 characters
NVARCHARVariable-length storage with a maximum length of 4,000 characters
NVARCHAR(max)Variable-length storage with provided max characters
NTEXTVariable-length storage with a maximum size of 1GB data

SQL Data Types important points

  • Not all data types are supported by every relational database vendor. For example, Oracle database doesn’t support DATETIME and MySQL doesn’t support CLOB data type. So while designing database schema and writing SQL queries, make sure to check if the data types are supported or not.
  • Data types listed here doesn’t include all the data types, these are the most popularly used data types. Some relational database vendors have their own data types that might be not listed here. For example, Microsoft SQL Server has money and smallmoney data types but since it’s not supported by other popular database vendors, it’s not listed here.
  • Every relational database vendor has its own maximum size limit for different data types, you don’t need to remember the limit. Idea is to have the knowledge of what data type to be used in a specific scenario.
What is Database Language ? Its Types | Data Type SQL
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