SQL Databases

What is a SQL Database?

A SQL database is a collection of structured data stored in a relational model. SQL databases organize data into tables, rows, and columns, making it easier to retrieve, manage, and update information. The data is stored in a way that ensures its integrity and consistency.

Relational databases use SQL (Structured Query Language) as the standard language to interact with the data. This makes SQL databases powerful tools for managing large amounts of data efficiently.

Components of a SQL Database

A typical SQL database consists of the following components:

• Tables: Collections of related data, organized in rows and columns.
• Rows (Records): Individual entries in a table.
• Columns (Fields): Attributes of the data stored in a table, defining the data type for each entry.
• Indexes: Structures that improve the speed of data retrieval operations.
• Keys: Unique identifiers for each record in a table, such as Primary and Foreign Keys.
• Constraints: Rules applied to tables and fields to maintain data integrity (e.g., NOT NULL, UNIQUE).

Creating a Database in SQL

To create a new database in SQL, you can use the CREATE DATABASE statement. Below is an example of creating a new database:

CREATE DATABASE mydatabase;

Once a database is created, you can create tables within it to store your data.

Common SQL Database Operations

SQL provides various commands to manage and manipulate databases. Here are some common operations:

• Creating Tables: Use the CREATE TABLE command to define new tables within a database.
• Inserting Data: Use the INSERT INTO command to add new records to a table.
• Updating Data: Use the UPDATE command to modify existing records in a table.
• Deleting Data: Use the DELETE command to remove records from a table.
• Selecting Data: Use the SELECT command to query and retrieve data from a table.