The package provides following advantages:
- Modularity
- Easy to design the applications
- Better performance
- Hiding information
- Added functionality
- Overloading
In the context of IBM Db2, a package is a database object that contains executable forms of one or more SQL statements. The use of packages in Db2 offers several advantages:
- Performance Optimization:
- Precompiled Execution: Packages allow SQL statements to be precompiled, optimizing the execution plan for better performance. This precompilation process reduces the overhead of parsing and optimizing SQL statements each time they are executed.
- Reuse of Execution Plans: Once a package is created, it can be reused by multiple application programs. This reuse of execution plans improves overall system performance by avoiding redundant compilation and optimization.
- Security:
- Access Control: Packages provide a level of access control. Users can be granted access to execute a specific package without necessarily having direct access to the underlying SQL statements. This helps in enforcing security policies.
- Encapsulation: SQL statements within a package can be encapsulated, reducing the exposure of the underlying database structure to application developers.
- Resource Management:
- Bind and Rebind Operations: Packages are created and bound to the database, linking the SQL statements with the database schema. The ability to bind and rebind packages allows for efficient resource management and adaptability to changes in the database schema.
- Maintenance and Versioning:
- Isolation of Changes: Changes to individual SQL statements can be isolated within a package. This helps in managing and maintaining code, especially in large and complex database applications.
- Versioning: Different versions of a package can coexist, allowing for gradual application upgrades without impacting the entire system.
- Parameterization:
- Parameter Markers: Packages support the use of parameter markers, allowing for the parameterization of SQL statements. This facilitates the creation of dynamic SQL, where parameters can be substituted at runtime.
In summary, using packages in Db2 provides performance benefits, enhances security, simplifies resource management, and aids in code maintenance and versioning.