Introduction

July 2016 ยท 1 minute read

This is a reference to what I have found interesting about Postgres.

Database Languages

Data Definition Language (DDL)

It is the database schema (Data fields , Data Types , Constraints). Example: CREATE TABLE student(SNAME CHAR(10), ROLLNO CHAR(10))

Data Manipulation Language (DML)

It is used for data manipulation. Data manipulation is retrieval, insertion, deletion and updating of information stored in the database.

ACID Transactions

  • Atomic: Everything in the transaction is part of a single ‘atom’. Either everything succeeds or everything fails.
  • Consistent: Both the starting and finishing state of the transaction are valid and do not violate any database rules.
  • Isolated: Transactions are isolated from each other and can not interfere with each other.
  • Durable: All completed transactions persist permanently.

PostgreSQL vs. MS SQL Server