A database language is a computer language used to manipulate and query data in a database. It consists of a set of commands, syntax, and keywords used to perform specific tasks. There are different database languages, each designed for a particular purpose.
In this article, we will explore more on types of database languages and what sets them apart from each other. Let’s get started!
Data Manipulation Language (DML)
Data Manipulation Language (DML) is a family of database languages used to manipulate data stored in a database. To be more specific, it enables the users/administrator to interact with the data in a database by issuing commands. The main focus of a DML is to provide an easy and efficient way for users to insert, update, delete or query data.
The commands of DML is as follows:
- SELECT: It is used to extract data from a database. You can use the SELECT statement to return all or part of the data in a table.
- INSERT: You can use this command to add new data to a table.
- UPDATE: With the update command, you can update existing data in a table.
- DELETE: This command is used to delete or remove data from a table.
Data Manipulation Language (DML) is also categorized into two types: Procedural DML or Non-procedural DML.
In procedural data manipulation, the user specifies what data is needed and how to get it. It requires a detailed understanding of the data and the relationships between them. The main advantage of procedural DML is that it is easier to understand and use.
In non-procedural data manipulation, the user specifies what data is needed but not how to get it. Non-procedural DML is more flexible and easier to use than procedural DML. The main disadvantage of non-procedural DML is that it requires a detailed understanding of the database structure.
Data Definition Language (DDL)
Database administrators use Data Definition Language (DDL) to create and manage a database structure. This includes defining tables, columns, and relationships between tables. DDL can also be used to create and manage indexes and views. Moreover, with DDL, you can alter the structure of the database, for example, to add or drop data.
The commands of Data Definition Language are:
- CREATE: The command is used to create a table, index, or view.
- DROP: Drop command is used to delete an object from the database.
- ALTER: It is used to change the properties of an existing object in the database.
- TRUNCATE: The command deletes all data from a table while preserving the table structure.
Transaction Control Language (TCL)
Transaction Control Language (TCL) is used to manage transactions in a database. Transactions are a set of SQL commands that are executed as a single unit. The tasks need to be completed in order for the transaction to be successful.
Commands of TCL are as follows:
- COMMIT: This command saves all the changes made by the transaction.
- ROLLBACK: This command is used to undo all the changes made by the transaction.
- SAVEPOINT: This command is used to create a savepoint, which is a marker that is used to identify a specific point in a transaction.
- SET TRANSACTION: This command is used to set the characteristics of a transaction.
Data Control Language (DCL)
Data Control Language (DCL) is a database language used to define and control the access of users to data stored in a database. It doesn’t manipulate the data; it just defines who can do what with the data. It’s like a security guard for your data. By using DCL, administrators can permit or cancel access privileges to users.
Some of the DCL commands are as follows:
- GRANT: It is used to give a user access privileges to the database.
- REVOKE: It can take away a user’s access privileges to the database.
- LOCK TABLE: Used to lock a database table so that only one user can access it at a time.
- UNLOCK TABLE: As the name suggests, it can unlock a database table.
Most Popular Database Languages
Below are some of the most popular and widely used database languages:
XQuery is a language for querying XML data. It is widely used in enterprises because it can query both XML and relational data. XQuery can be used to query databases that store XML data, such as eXist or MarkLogic.
SQL (Structured Query Language) is the most popular database language. It is used to query relational databases such as MySQL, Oracle, Microsoft SQL Server, and PostgreSQL. You can create, read, update, and delete data in a relational database using SQL.
NoSQL is a popular alternative to SQL for storing and querying data. NoSQL databases are designed to handle unstructured and semi-structured data. Some of the most popular NoSQL databases are MongoDB, Cassandra, and NeoJSON.
OQL (Object Query Language) is a database language used to query object-oriented databases. OQL is the native language of Objectivity/DB, a popular object-oriented database system.
PL/SQL is a procedural extension of SQL that is used in Oracle databases. PL/SQL includes features such as loops, conditional statements, and exception handling.
Which Database Language Should You Learn?
Which database language you should learn depends on what type of data you want to query. If you want to query XML data, then you should learn XQuery. If you want to query relational data, then you should learn SQL. If you need to query object-oriented data, then you should learn OQL.
Note that you don’t need to learn all of these languages. If you know one database language, then you can query any type of data. For example, if you know SQL, then you can use it to query XML data by using the XML functions in SQL.
So, these are the different types of database languages that you may encounter while working with databases. Each language has its own strengths and weaknesses, so it’s essential to understand them all. We hope the article helped understand the different types of database languages.
If you have any questions, feel free to ask in the comments section below. Thanks for reading!