SQL stands for structured query language. It is sometimes pronounced as ‘Se—quel’. It is the standard language for retrieving, storing and manipulating stored data in a Relation Database System. Therefore, it is regarded as the standard database language used in relational database management systems like Informix, MS Access, Sybase, Postgres, MySQL , Oracle and SQL servers. As a computer programming language, SQL is, however, different from COBOL, Java ,Python and the rest because it is a non-procedural language but can be used in conjunction to provide efficient access to data.
Differences between a Procedural and Non-procedural Programming language
A procedural language explains how and the order an application’s operation should be performed, for example, Java, while a non-procedural language is less concerned with that but more on the results of an application’s operation.
THE SQL ARCHITECTURE
SQL Query—-> Query language Processor—->DBMS Engine—–> Physical Database.
Definition of Terms
Moving on, you might be wondering what DBMS means, so another way to be familiar with the terminologies. Below are some terms used in SQL.
1. Database: This is a collection of data organized in a structured format and defined by metadata that describes that structure.
2. RDBMS: is the basis of SQL and it connotes Relational Database Management System.
3. Metadata: it is data or structured information about a file stored within a database.
4. Table: it is a database object that stores data.
5. Field: this includes the smaller entities of a table.
6. Column: it is a vertical entity in a table that contains all information associated with a specific field.
7. Record: is a row of data that exists in a table.
SQL Basic Commands and Functions
* Select: it retrieves certain records from one or more tables.
* Update: it modifies records.
* Create: it creates new tables or a view of a table in the database.
* Insert: it creates a record.
* Drop: It deletes an entire table from a database.
* Delete: it deletes records.
TYPES OF SQL STATEMENTS
Every SQL statement starts with any of the commands like select, update, create, insert, delete, drop, else, show, alter and they all end with a semi-colon(;)
Based on the functions they perform, SQL can be separated into three types of statements. They are:
∆ Data Manipulation Language (DML): these statements are used to modify, retrieve and delete stored data in a database. The primary keywords are INSERT, DELETE, UPDATE, and SELECT.
∆ Data Control Language (DCL): these statements allow for the control of who and what has access to specific data in a database. GRANT and REVOKE are commands used to restrict and constrict users’ privileges.
∆ Data Definition Language (DDL): These statements can be used to create, modify or even delete database objects. These keywords include DROP, ALTER and CREATE.
Recently, almost everyone, if not all, has to work with data. This has made data scientists and data analysts more popular than they used to be because of their work with data and it also explains why one of the most common database structures is the relational database. SQL is quite critical and is one of the most in-demand skills listed in 57.4% of all data scientist/analyst job requirements.
WHAT ARE THE SPECIFIC BENEFITS OF SQL?
∆ It is easy to learn: SQL syntax depends on our everyday English words, which makes it easily understood in its usage.
∆ It can select and create new databases.
∆ It can insert, delete, and update records in a database.
∆ It allows users to define the data in a database and manipulate the same data.
∆ It allows users to set permissions or constraints in tables.
∆ It allows the users to describe the data.
∆ It makes you more qualified for data-based careers.
To practice the use of SQL anywhere and at any time, download the software, e.g MySQL community server and MySQL Workbench, then create your first database and table, thereafter get some data and keep getting curious about it.
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