ACID Properties in DBMS

ACID properties of a transaction in a relational model are as follows:

1. Atomicity: This property ensures that either the transaction happens completely or doesn't happen at all. Every transaction causes some data values in a table to either delete or update. It may also add a new row to the table. It is necessary that when a transaction happens, either all data values or rows are updated or none of the values is changed.
2. Consistency: This property ensures that the data is consistent in every table. Data before and after a transaction is made must be consistent.
3. Isolation: If two transactions are happening at the same place, either they should be independent of each other or one of these transactions must happen first. 
4. Durability: Every transaction must be durable. This means that if a transaction occurs, then the changes made by this transaction to the database remain even in the event of a system failure.