Introduction to SQL

SQL provides a standard way to create, read, update, and delete data, as well as to manage the database structure and configuration.

Commands like CREATE TABLE, ALTER TABLE, and DROP TABLE are used to create, modify, and delete database objects.

The SELECT statement is used to retrieve data from one or more tables based on specific criteria.

The WHERE clause is used to filter data based on specific criteria.

The JOIN clause is used to combine data from multiple tables based on related columns.

The four primary operations are create, read, update, and delete (CRUD).

To filter data based on a specific condition

SELECT column1, column2,...FROM table_name ORDER BY column ASC|DESC;

Using the INSERT INTO statement

To ensure data integrity by completing a series of operations as a single unit.

To ensure data integrity and enforce business rules.

To modify existing data in a table

To remove records from a table

To simplify complex queries and provide data abstraction.

To perform aggregate functions on a dataset

To encapsulate complex logic and execute it on the database server.

To retrieve data from one or more tables in a database.

To retrieve data from multiple related tables

The process of organizing data to minimize redundancy and ensure data integrity

To filter data based on a specified condition or criteria.

To sort the resulting data in ascending or descending order.

Avoiding data redundancy, improving data integrity, simplifying data maintenance, optimizing query performance, and facilitating scalability

To group rows that have the same values into summary rows.

To optimize performance, ensure data integrity, and facilitate data management

To combine rows from two or more tables based on a related column between them.

To interact with relational databases in a standardized and efficient manner.

Normalizing a database eliminates redundancy, reduces the likelihood of data anomalies, and improves data integrity and efficiency by breaking down data into smaller, related tables.

Choosing the appropriate data type for each column ensures efficient storage, reduces storage space, and improves data integrity.

Foreign keys establish relationships between tables, enforcing data integrity and maintaining consistency by ensuring referential integrity and preventing data anomalies.

Indexing improves query performance by allowing the database to quickly locate and retrieve data, reducing the time it takes to execute queries.

Normalization improves data integrity but can negatively impact performance, while denormalization optimizes query performance but can compromise data integrity; a balance must be struck based on application requirements.

Regular maintenance tasks, such as updating statistics and reorganizing indexes, ensure the database remains efficient, responsive, and healthy, preventing performance degradation and data corruption.