Grant Usage vs Grant Select: What is the Difference?
When it comes to managing user privileges within a database, there are several options to choose from. Two of the most common options include granting users the ability to use specific objects within the database, or granting them the ability to select specific data from those objects. These options are known as “grant usage” and “grant select”. In this blog post, we will explore the difference between these two options.
Grant Usage
When you grant a user “usage” on an object within the database, you are giving them the ability to perform any operation that does not modify the data within that object. For example, if you grant a user “usage” on a table, they would be able to execute a “SELECT” statement on that table, but they would not be able to execute an “UPDATE” statement.The syntax for granting usage on an object is as follows:
GRANT USAGE ON [object] TO [user];
The object in this case could be a table, view, sequence, or even a schema. The user could be a specific user within the database or a database role.One common use case for granting usage is when you have multiple applications accessing the same database. Each application may only need access to specific tables or views within the database, but you don’t want to give them the ability to modify any of the data within those objects. In this case, you could grant them “usage” on those objects.
Grant Select
When you grant a user “select” on an object within the database, you are giving them the ability to retrieve data from that object using a “SELECT” statement. This means they can view the data contained within the object, but they cannot modify it in any way.The syntax for granting select on an object is as follows:
GRANT SELECT ON [object] TO [user];
As with granting “usage”, the object in this case could be a table, view, sequence, or schema, and the user could be a specific user or a database role.One common use case for granting select is when you have a reporting application that needs to extract data from a specific table within the database. In this case, you could grant the reporting user “select” on that table, but not any other privileges.
Underlying Differences
While both “grant usage” and “grant select” provide the user with read-only access to objects within the database, there are some underlying differences between the two.The first difference is that “usage” applies to all operations that do not modify the data, while “select” is specifically for retrieving data. This means that if you grant a user “usage” on a schema, they will be able to execute a “CREATE TABLE” statement within that schema, but they will not be able to read any data from existing tables within that schema.The second difference is that “usage” can be granted at the schema level, while “select” is always granted at the object level. This means that if you want to grant a user read-only access to every object within a schema, you can do so by granting them “usage” on that schema.
Conclusion
In conclusion, the difference between “grant usage” and “grant select” within a database is that “usage” applies to all operations that do not modify data, while “select” is specifically for retrieving data. Both options provide read-only access to objects within the database, but “usage” can be granted at the schema level, while “select” is always granted at the object level.When managing user privileges within a database, it’s important to consider which option is most appropriate for each user or application. By understanding the differences between “grant usage” and “grant select”, you can ensure that users only have the access they need to perform their specific tasks, without compromising the security or integrity of your data.