APIs in Oracle HRMSAn Application Programmatic Interface (API) is a logical grouping of external process routines. The Oracle HRMS strategy delivers a set of PL/SQL packaged procedures and functions that together provide an open interface to the database. For convenience we have called each of these packaged procedures an API.

API OverviewFundamental to the design of all APIs in Oracle HRMS is that they should provide an insulating layer between the user and the data-model that would simplify all data-manipulation tasks and would protect customer extensions on upgrade. They are parameterized and executable PL/SQL packages that provide full data validation and manipulation.The API layer enables us to capture and execute business rules within the database - not just in the user interface layer. This layer supports the use of alternative interfaces to HRMS, such as web pages or spreadsheets, and guarantees all transactions comply with the business rules that have been implemented in the system. It also simplifies integration of Oracle HRMS with other systems or processes and provides supports for the initial loading

Alternative User Interfaces

The supported APIs can be used as an alternative data entry point into Oracle HRMS. Instead of manually typing in new information or altering existing data using the online forms, you can implement other programs to perform similar operations.These other programs do not modify data directly in the database. They call the APIs which:

1. Ensure it is appropriate to allow that particular business operation2. Validate the data passed to the API

3. Insert/update/delete data in the HR schema

APIs are implemented on the server-side and can be used in many ways. For example:

Customers who want to upload data from an existing system. Instead of employing temporary data entry clerks to type in data, a program could be written to extract data from the existing system and then transfer the data into Oracle HRMS by calling the APIs.

Customers who purchase a number of applications from different vendors to build a complete solution. In an integrated environment a change in one

application may require changes to data in another. Instead of users having to remember to go into each application repeating the change, the update to the HRMS applications could be applied electronically. Modifications can be made in batches or immediately on an individual basis.

Customers who want to build a custom version of the standard forms supplied with Oracle HRMS. An alternative version of one or more forms could be implemented using the APIs to manage all database transactions.

Customers who want to develop web-based interfaces to allow occasional users to access and maintain HR information without the cost of deploying or supporting standard Oracle HRMS forms. This is the basis of most Self-Service functions that allow employees to query and update their own information, such as change of name, address, marital status. This also applies to managers who want to query or maintain details for the employees they manage.

Managers who are more familiar with spreadsheet applications may want to export and manipulate data without even being connected to the database and then upload modifications to the HRMS database when reconnected.

In all these examples, the programs would not need to modify data directly in the Oracle HRMS database tables. The specific programs would call one or more APIs and these would ensure that invalid data is not written to the Oracle HRMS database and that existing data is not corrupted.

Advantages of Using APIs

Why use APIs instead of directly modifying data in the database tables? Oracle does not support any direct manipulation of the data in any application using PL/SQL. APIs provide you with many advantages:

APIs enable you to maintain HR and Payroll information without using Oracle forms.

APIs insulate you from the need to fully understand every feature of the database structure. They manage all the inter-table relationships and updates.

APIs are guaranteed to maintain the integrity of the database. When necessary, database row level locks are used to ensure consistency between different tables. Invalid data cannot be entered into the system and existing data is protected from incorrect alterations.

APIs are guaranteed to apply all parts of a business process to the database. When an API is called, either the whole transaction is successful and all the individual database changes are applied, or the complete transaction fails and the database is left in the starting valid state, as if the API had not been called.

APIs do not make these changes permanent by issuing a commit. It is the responsibility of the calling program to do this. This provides flexibility between individual record and batch processing. It also ensures that the standard commit processing carried out by client programs such as Forms is not affected.

APIs help to protect any customer-specific logic from database structure changes on upgrade. While we cannot guarantee that any API will not change to support improvements or extensions of functionality, we are committed to minimize the number of changes and to provide appropriate notification and documentation if such changes occur.

Note: Writing programs to call APIs in Oracle HRMS requires knowledge of PL/SQL version 2. The rest of this essay explains how to call the APIs and assumes the reader has knowledge of programming in PL/SQL.