What is the purpose of PostgreSQL?

Vaibhav Kothia May 26, 2023 0 Comments

PostgreSQL is an open source object-relational database management system (ORDBMS) that is used to store and retrieve data. It is designed to handle large datasets and complex queries, and is used by many organizations for mission-critical applications.

For example, PostgreSQL can be used to store customer information for an e-commerce website, store financial records for a bank, or store medical records for a hospital. PostgreSQL provides a robust set of features that make it well-suited for these types of applications. It also provides scalability, reliability, and high performance.

How do you create a database in Oracle?

Vaibhav Kothia May 26, 2023 0 Comments

In Oracle, you can create a database by using the CREATE DATABASE statement.

For example, the following statement creates a database named “testdb” with the default settings:

CREATE DATABASE testdb;

What are the different types of Oracle Database objects?

Vaibhav Kothia May 26, 2023 0 Comments

1. Tables: A table is a collection of related data stored in a structured format within a database. For example, a customer table might contain the columns customer_id, first_name, last_name, email, and address.

2. Views: A view is a virtual table based on the result set of an SQL statement. For example, a view might contain all customer records from the customer table who have an email address.

3. Indexes: An index is a performance-tuning method of allowing faster retrieval of records. For example, an index on the customer_id column of the customer table would allow faster retrieval of customer records.

4. Sequences: A sequence is an object used to generate unique numbers. For example, a sequence might be used to generate customer_id numbers for new customer records.

5. Stored Procedures: A stored procedure is a set of SQL statements that can be stored in the database and executed as a single unit. For example, a stored procedure might be used to generate a report based on a set of parameters.

6. Triggers: A trigger is a stored procedure that is executed when a certain event occurs. For example, a trigger might be used to update a customer’s address when their record is updated in the customer table.

What is Oracle Database and why is it used?

Vaibhav Kothia May 26, 2023 0 Comments

Oracle Database is an object-relational database management system (ORDBMS) developed by Oracle Corporation. It is used to store and manage data for large applications, web sites, and other distributed applications. Oracle Database is used to store, organize, and retrieve data in a secure and efficient manner. It is also used to create and manage databases for web applications, data warehouses, and other applications. For example, Oracle Database can be used to store customer information, product information, and financial data. It can also be used to create and manage databases for e-commerce websites, data warehouses, and other applications.

What is the purpose of the PostgreSQL vacuum command?

Vaibhav Kothia May 26, 2023 0 Comments

The PostgreSQL vacuum command is used to reclaim storage space and prevent transaction id wraparound. It is an important maintenance command that helps maintain the performance and integrity of the database.

Vacuuming is done to remove old data that is no longer needed. This can be done manually with the VACUUM command.

Example:

To vacuum the table ‘users’ and reclaim any unused space:

VACUUM users;