To maintain the integrity of a database, all transactions must obey the ACID properties. ACID is an acronym for Atomicity, Consistency, Isolation and Durability.

The ACID properties are as follows:

• Atomic: This property ensures that either all the operations of a transaction reflect in database or none. If one part of the transaction fails, the entire transaction fails and the database state is left unchanged.
• Consistency: The consistency property ensures that the database remains in a consistent state before the start of the transaction and after the transaction is over (whether transaction is successful or not).
• Isolation: Modifications of data performed by a transaction must be independent of another transaction. Isolation states that there every transaction in a database must be independently executed without interference.
• Durability: Durability refers to the guarantee that once transaction completes successfully, the changes made into the database should be permanent even if there is a software or hardware failure.

Apart from these ACID properties, there are some basic characteristics due to which Relational DBMS become popular. Some of them are:

Data is stored in a set of Tables or data is stored in the format of row and column in a table.

• Relationships are represented by data.
• Tables are joined by relational links.
• Reduced duplication of data in database can be achieved by normalization.
• They allow greater flexibility and efficiency