SQL (Structured Query Language) is a programming language used to communicate with and manipulate data stored in relational databases such as Oracle databases. Oracle databases are widely used in enterprise-level applications for their scalability, reliability, and security features.
SQL is used in Oracle databases for a variety of functions, including:
1. Retrieving data - SQL queries can retrieve specific data that meets certain criteria or conditions from a table or multiple tables.
Example:
SELECT * FROM employees WHERE department = 'Sales';This query retrieves all the information from the employees table where the department is ’Sales’.
2. Inserting data - SQL is used to insert new data into a table.
Example:
INSERT INTO employees (name, department, salary) VALUES ('John Smith', 'Marketing', 50000);This query inserts a new record into the employees table with the name ’John Smith’, department ’Marketing’, and salary 50000.
3. Updating data - SQL is used to update existing data in a table.
Example:
UPDATE employees SET salary = 55000 WHERE name = 'John Smith';This query updates the salary of the employee named ’John Smith’ to 55000.
4. Deleting data - SQL is used to delete records from a table.
Example:
DELETE FROM employees WHERE department = 'Marketing';This query deletes all records from the employees table where the department is ’Marketing’.
In addition to these basic functions, SQL can also be used to create and modify database objects such as tables, views, and procedures.
Overall, SQL is a powerful tool for managing and manipulating large amounts of data in Oracle databases.