The Structured Query Language (SQL) is a standard language for communicating with your relational SQL database. After data collection and database design using tools such as Entity Relationship Diagram, a database programmer then uses SQL to implement the design in Relational Database Management System (RDBMS).
A SQL database is structured on E F Codd’s (Mathematician who came up with the relational database model) database rules. It allows us to store, retrieve and manage data stored in a database. Almost all modern RDBMSs rely on the language for all their data operations.
No matter the variant used by the RDBMS developer, they share a number of common traits. Not only is the language easy to learn, since it uses English words, but the command structure has similar components.
Data Definition Language
Using keywords such as CREATE, DROP, RENAME, TRUNCATE and ALTER, a database programmer can change the structure of a database. When executed, DDL statements are permanent and can not be reversed. As such, great care is to be taken when using them.
Data Manipulation Language
To assist in manipulation of data stored in a SQL database, SQL includes DML commands such as INSERT, DELETE, UPDATE and MERGE. Unlike DDL commands, DML commands are not automatically committed (made permanent). They can be reversed during a rollback.
Data Control Language
Access and permissions are crucial in RDBMSs. Access refers to which individuals or procedures are permitted to have access to a SQL database file. For those that have a grant to access a SQL database, what they do with the data also needs to be closely governed, hence permissions. SQL helpfully gives us the ability to do this through its DCL component. Using commands such as GRANT and REVOKE, we grant or take back privileges from database users.
Transaction Control Language
Using commands such as COMMIT, ROLLBACK, and SAVEPOINT, we can check other commands ran by database users and affect their permanence in our database. The commands can nullify other commands or commit them to make them permanent.
Data Query Language
Most of the activities carried out in the database environment fall into this category. They usually include the SELECT and SHOW commands. They are used to get data back from database tables. The command can be refined by including other clauses (keywords) such as WHERE.
Benefits of using SQL
1 The language allows one to view data from SQL database tables without necessarily saving the data
2 You can query more than one database table and display the data in one table
3 It offers a much easier way of limiting access to our data using DCL commands
4 Compared to other data storage methods, the language is efficient and fast in data retrieval
5 With minimal coding, you can model or develop complex relationships
Though there are numerous benefits, you need to keep in mind that there might be a slightly steep learning curve in the beginning. Nonetheless, since it is largely English based, most developers find it easy to pick up. Also, different software developers add different extensions to their platforms. Therefore, when migrating to a new platform, developers might be required to relearn some of the features in the new platform. This is to the software developer’s benefit to ensure customer lock-in. This, however, is a small price to pay for core component in any business.