Techniques for adding multiple security policies to a database system

1. A method for managing access to data in a database subject to a plurality of label-based security policies, the method comprising the steps of:

receiving, a request for performing an operation set of one or more operations on data in a table of the database;

determining which policies, of the plurality of label-based security policies, apply to the table based on a policy set of one or more policies associated with the table;

for each operation in the operation set, determining whether to perform the operation on a row of the table based on a set of labels associated with the row, the set of labels corresponding to the policy set;

adding, to the table, a first policy column that stores labels for a first policy of the policy set that has a first policy type that is selected from the group consisting of: (a) a compartmented policy type in which a label associated with a particular row must exactly match a subject's label in order for the subject to gain access to the particular row, (b) a multi-level policy type in which a label associated with the particular row must be at a same or lower level of security than a level of security associated with the subject in order for the subject to gain access to the particular row, and (c) a hierarchical policy type in which a label associated with the particular row must be at a same level of security associated with the subject or at a lower level on a same branch of a hierarchy that contains the level of security associated with the subject in order for the subject to gain access to the particular row; and

adding, to the table, a second policy column that stores labels for a second policy of the policy set that has a second policy type that is selected from the group;

wherein the first policy type differs from the second policy type; and

wherein the method is executed by a database management system comprising one or more computer systems.

2. A method according to claim 1 , further comprising adding a policy column to the table for each policy in the policy set associated with the table.

3. A method according to claim 2 , further comprising storing a label, of the set of labels associated with the row, in a corresponding policy column of the row.

4. A method according to claim 2 , said step of determining which policies apply further comprising the step of determining whether a column is a policy column.

5. A method according to claim 1 , wherein the policy set associated with the table includes two or more policies of the plurality of label-based security policies.

6. A non-transitory computer-readable storage medium storing one or more sequences of instructions for managing access to data in a database subject to a plurality of label-based security policies, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

receiving a request for performing an operation set of one or more operations on data in a table of the database;

determining which policies, of the plurality of label-based security policies, apply to the table based on a policy set of one or more policies associated with the table;

for each operation in the operation set, determining whether to perform the operation on a row of the table based on a set of labels associated with the row, the set of labels corresponding to the policy set;

adding, to the table, a first policy column that stores labels for a first policy of the policy set that has a first policy type that is selected from the group consisting of: (a) a compartmented policy type in which a label associated with a particular row must exactly match a subject's label in order for the subject to gain access to the particular row, (b) a multi-level policy type in which a label associated with the particular row must be at a same or lower level of security than a level of security associated with the subject in order for the subject to gain access to the particular row, and (c) a hierarchical policy type in which a label associated with the particular row must be at a same level of security associated with the subject or at a lower level on a same branch of a hierarchy that contains the level of security associated with the subject in order for the subject to gain access to the particular row;

adding, to the table, a second policy column that stores labels for a second policy of the policy set that has a second policy type that is selected from the group; and

wherein the first policy type differs from the second policy type.

7. The non-transitory computer-readable storage medium according to claim 1 , wherein execution of the one or more sequences of instructions further causes the one or more processors to perform the step of adding a policy column to the table for each policy in the policy set associated with the table.

8. The non-transitory computer-readable storage medium according to claim 7 , wherein execution of the one or more sequences of instructions further causes the one or more processors to perform the step of storing a label, of the set of labels associated with the row, in a corresponding policy column of the row.

9. The non-transitory computer-readable storage medium according to claim 7 , said step of determining which policies apply further comprising the step of determining whether a column is a policy column.

10. The non-transitory computer-readable storage medium according to claim 6 , wherein the policy set associated with the table includes two or more policies of the plurality of label-based security policies.