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