Data is the most valuable asset in today’s world as it helps organizations as well as individuals to extract information and use it to make various decisions. To make the retrieval and maintenance of data easy and efficient, data is stored in a database. All the operations of data manipulation and maintenance are done using Database Management System. Databases are a favourite target for attackers because of the data stored in the databases and also because of their volume. There are many ways a database can be compromised. Considering the importance of data in organization, it is absolutely essential to secure the data present in the database. The basic problems are access control, exclusion of spurious data, authentication of users and reliability. In this paper the challenges and threats in database security are identified.