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New DB2 table model which minimizes number of tables and allows higher scalability

IP.com Disclosure Number: IPCOM000014263D
Original Publication Date: 2001-Jan-01
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue



This disclosure contains an explanation of the layout and usage of the LDAP (Lightweight Directory Access Protocol) Directory Services physical schema and provide examples to clarify concepts, where appropriate. The layout defined is independent of the types of directory entries being stored and also minimizes the number of tables required to store and search directory entries. In some relational database implementation for LDAP unique tables are created for each attribute defined in the directory. Because of the large number of tables generated the database over time becomes unmanageable which limited scalability. The table layout is comprised of three logical table types, entry table, descendants table and search table. The entry table is used to store the unnormalized directory entry, the distinguished name of the entry, and access control information for the entry. The decedents table identifies the hierarchical relationships between directory entries and the search table contains the normalized values of the information contained in a directory entry. All searches supported by the LDAP Directory can be performed by accessing these three tables. Each entry in the directory is assigned a unique identifier (EID) that is used to reference rows in the entry, descendants and/or search tables. There are three tables used to represent entry data in LDAP. The DIR_ENTRY table stores information specific to the entry, as well as the original entry data. The DIR_LONGENTRY table stores original entry data for entries whose size is greater than can be stored in one row in the DIR_ENTRY table. In the interest of reducing the retrieval time for entry data when the very large attribute values are not the target of the retrieval, the DIR_LONGATTR table stores original (unnormalized) attribute data for entries whose size is greater than some pre-configured attribute length threshold . If the size of any attribute values results in storing them in the DIR_LONGATTR table, these attribute values will not be duplicated in the ENTRYDATA columns of either the DIR_ENTRY table or the DIR_LONGENTRY table. The DIR_ENTRY table contains the following columns: