What data types are commonly used in RDBMS?

Common data types used in RDBMS include integer, float, char, varchar, date, time, and boolean.

In a Relational Database Management System (RDBMS), data types are used to define the kind of data that can be stored in a particular column of a table. These data types help to ensure data integrity by restricting the type of data that can go into a table. This ensures that the database behaves in a predictable manner and more importantly, that it does the right thing with the data. For a deeper understanding, check out our notes on data types in RDBMS.

The integer data type is used to store whole numbers. This could be either positive or negative numbers, but without any decimal points. The float data type, on the other hand, is used to store real numbers, which are numbers with decimal points.

The char and varchar data types are used to store strings. The difference between the two is that char is used for fixed length strings while varchar is used for variable length strings. For example, if you have a column that is defined as char(5), it will always store 5 characters. If you store 'abc', it will be stored as 'abc '. On the other hand, if you have a column that is defined as varchar(5), it can store up to 5 characters but it doesn't have to be 5 characters. If you store 'abc', it will be stored as 'abc'. Understanding these differences is crucial for appropriate data type selection.

The date and time data types are used to store date and time values respectively. The date type is used to store year, month, and day values. The time type is used to store hour, minute, and second values.

Lastly, the boolean data type is used to store true or false values. This is often used for columns that need to store a yes/no or true/false value. For more detailed explanations, refer to our section on understanding data types.

IB Computer Science Tutor Summary: In RDBMS, various data types like integer, float, char, varchar, date, time, and boolean determine the kind of data stored in a database's columns. These include integers for whole numbers, floats for numbers with decimals, chars and varchars for fixed or variable length strings, date and time for storing temporal values, and boolean for true/false values.