BLOB data type is a data type with varying length binary string. It is used to store two gigabytes memory. For BLOB data type, the length needs to be specified in bytes.

In Oracle, BLOB stands for Binary Large Object. It is a data type used to store binary data, such as images, audio, video, or other multimedia objects. BLOB can store large amounts of data, and it is often used when you need to store and retrieve binary data in its raw format.

When you define a column as BLOB in an Oracle database table, it means that the column will store binary data, and Oracle will not attempt to interpret or manipulate the contents of the data. BLOBs are commonly used to store multimedia files or any type of data that is not plain text.

For example, the syntax to create a table with a BLOB column might look like this:

CREATE TABLE my_table (

id NUMBER,

binary_data BLOB

);

This creates a table called my_table with a column named binary_data of type BLOB, which can be used to store binary data.