Architectural Principles Indexes
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Unique Indexes
Singleton columns with supporting unique indexes are useful in many circumstances. For example, the spatially enabling methodology created in 2002 – 2003 requires the use of a unique identifier for use in ESRI’s Geodatabase.
The PPDM Association has provided early support for globally unique indexes in PPDM version 3.7 through a column called PPDM_GUID (varchar2(38)). If your implementation will use this column, implementers will need to add unique indexes and NOT NULL constraints to use it correctly. DDL commands to do this are included in the PPDM data model deliverables. The PPDM compliance measurement process will be modified to ensure that implementations that use this are not penalized for modifying the DDL.
Index On Foreign Keys
PPDM provides a starter set of indexes for every foreign key constraint defined in PPDM. These Indexes should not be considered a final solution, but as a starter to assist in developing a suite of indexes based on site requirements.
We recommend that indexes be placed on the foreign keys, but recognize that too many indexes create their own set of problems. Please examine your implementation requirements and make decisions based on your need for query and update functions.
Guidelines
1. PPDM will not attempt to provide a set of performance indexes.
2. PPDM will provide index DDL for foreign key columns. If necessary, PPDM has a script that can be used to generate appropriate indexes and then reverse engineer index DDL from an installed database.
3. PPDM will not provide index DDL for non-foreign key columns.
Go to
- Architectural Principles Primary Key Constraints
- Architectural Principles Foreign Key Constraints
- Architectural Principles Check Constraints
- Architectural Principles Indexes
- Architectural Principles Arcs
- Architectural Principles Recursive Relationships
- Architectural Principles Naming Conventions
