Trade Study Purpose and Example of a Case Study
Trade study helps to evaluate products from different suppliers and it will support lawsuits from the suppliers who did not win the bids and sue the OEM later. Therefore, trade study serves the P3 strategy on the product side. This section provides the introduction to a relational database management system (RDBMS) trade study covering the background and purpose of the trade study, as well as the scope of effort of the study.
Purpose
This report presents the results of the trade study performed to select a commercial off-the-shelf (COTS) relational database management system software package to support Program-X development and maintenance.
Background
A COTS RDBMS is needed to support a Program-X database (DB). The key reason for PROGRAM-X (P-X) to select the relational model is based on its straightforward and easily understood conceptual model. A relational database consists of a set of tables. Each row in a relation represents a relationship between a set of values. Each table bears the name of a relation and contains rows and columns. New tables can be constructed from existing tables by cutting and pasting rows and columns. The DB will contain the complete source of the P-X Avionics interface (i.e., 1553, ARINC, RS-232, Discretes, Analog, etc.) information. The PROGRAM-X DB describes and coordinates the interface messages passed between line replaceable units (LRUs).
Scope of effort
The selected RDBMS meets the CCF AIDBS requirements. Theaddress the AIDBS/RDBMS requirements in more detail.
6.2.1.3.1 RDBMS data incorporation capability
6.2.1.3.1.1 RDBMS
The RDBMS shall have the capability to allow incorporation of:
- a. P-X design data from hardware specifications.
- b. P-X design data from drawings.
- c. P-X design data from specifications and be capable of expanding to six times.
RDBMS maintenance capability
RDBMS
The RDBMS electronic maintenance shall include the capability to:
- a. Maintain (backup, restore, archive, security, privileges and access control) the database.
- b. Modify (insert, update, and delete) the database.
- c. Query the database.
- d. Sort the database.
- e. Produce a hard copy form of the database.
- f. Produce the interface data of commercial version.
- g. Produce the interface data of interface control drawings.
Functional and Technical Design Requirements
This section identifies and lists the functional and technical design requirements for the RDBMS. The selected RDBMS meets these functional and technical design requirements described in Sections 6.2.2.1 and 6.2.2.2.
Functional requirements
The RDBMS will contain the complete source of P-X Avionics interface (i.e., 1553, ARINC, RS-232, Discretes, Analog, etc.) information. The RDBMS describes and coordinates the interface messages passed between LRUs. The selected RDBMS will be able to satisfy the DB functional requirements. Fig. 6.2.1 depicts the major functions of the DB: query, update/modify, maintain the database, and produce reports.
The P-X RDBMS has a menu-driven interface that allows access from Customer remote sites within the P-X software engineering environment. User-friendly options and clear, concise input forms allow users to query or modify any message contained within the DB application. The application allows the capability of managing multiple aircraft configurations and/or different versions of interfaces. The P-X DB customized report generators will create reports showing logical groupings of interface data.
Using industry-proven relational database management systems and fourth generation languages, the P-X team will create a database, populate, and verify its contents with current sources of Avionics interface information and Mission Computer Supplier Interface. We will explore the capability of employing the newly developed P-X DB application for existing Avionics. The result will yield a DB that meets the needs of the P-X into the future.
The requirement analysis has begun with the identification and acquisition of the existing P-X Avionics interface information. Company’s strategy for the RDBMS is to comply with the P-X System Specification: The P-X shall provide electronic maintenance capability for documentation of P-X Avionics interfaces in a database system. In summary, the RDBMS maintenance capabilities shall include:
- a. Maintain (backup, restore, archive, security, privileges and access control) the database.
- b. Modify (insert, update, and delete) the database.
- c. Query the database.
- d. Sort the database.
- e. Produce a hard copy form of the database.
- f. Produce the interface data of commercial version.
- g. Produce the interface data of interface control drawings.
Technical design requirements
The technical design of the DB begins by determining the best RDBMS software solution that complements the P-X Software Engineering Environment (SEE). The User Interface (UI) CSCI accesses the RDBMS through COTS Support Software CSCI. The selected RDBMS will be run under a specific OS environment.
The technical design of the P-X RDBMS is to support the DB functional requirements. Key technical design requirements of the RDBMS are categorized as follows:
- a. query the database,
- b. modify the database,
- c. insert new data into the database,
- d. develop and/or modify existing report generators,
- e. maintain the (backup, restore, archive, and security control ) database,
- f. able to run on a specific OS platform,
- g. support parallel server methodology, and
- h. support mirroring disk technique.
A Preliminary Design Review (PDR) will review the design with the customers. Upon approval of the Customer, it is then placed under configuration control.
RDBMS Evaluation
This section lists the relational database management systems considered and the significant characteristics of each system. In addition, this study is restricted to the characteristics and attributes of the P-X DB design approach that affects the current design feasibility and the system requirements. The significant evaluation criteria reflect final selection based on such factors as high availability, vendor stability, support record, portability from existing databases, interface friendliness, access security/integrity, and user programming.
RDBMS suppliers
Research was conducted to determine potential RDBMS suppliers in order to support P-X DB requirements. Five RDBMS suppliers were identified: Oracle 7.0, Informix Online 6.0, Sybase System 10, Open/Ingres, and Interbase 3.3. A set of selection criteria described in Section 6.2.3.2 was established to further down-select to one RDBMS.
RDBMS selection criteria
Seven selection criteria were used for this trade study.
The seven criteria are as follows:
High availability
Oracle is rated slightly higher because the users have continuous access to the ORACLE database even if only one node in the ORACLE Parallel Server is functioning. If a node goes down, then the ORACLE Parallel Server on the other nodes automatically recovers the down ORACLE instances. If even one node is available, that node can recover for all the other nodes and keep the database up. Sybase only supports the mirrored disk for the availability concept.
Vendor stability
Oracle and Sybase are both financially strong; however, Oracle has 44% of the market share, and Sybase only has 12%. Therefore, Oracle was rated higher than Sybase.
Support record
Oracle and Sybase are both growing at a rapid rate. A recent database magazine indicated Oracle was slightly better than Sybase in customer support. Therefore, both suppliers were rated poorly.
Portability
Oracle is rated higher because some Supplier Interface Control Drawing (SICD) information is already in the Oracle database form. Therefore, Oracle was given a higher score than Sybase.
Interface friendliness
The Oracle FORMS/MENU application was more friendly compared to Sybase APT Workbench. A screen can be developed faster with the Oracle FORMS application tool. Therefore, a higher rating was given to Oracle.
Access security/integrity
The Oracle RDBMS provides two general categories of security management: authorizing the userid and password of anyone that can connect to the database, and restricting the data (tables and views) that are accessible by each userid for insert, update, delete, and query. However, Sybase’s security method is about the same but its data integrity handling fell short compared to Oracle. Therefore, Oracle was rated higher than Sybase.
6.2.3.2.7 User programming
Application development/user programming for Oracle and Sybase is rated as equal because Oracle has SQL⁎Plus and Sybase has APT-Build. These automatic application generators were both rated equally.
RDBMS analysis results
Two RDBMSs (Oracle and Sybase) have been benchmarked for the P-X DB. The benchmark results are shown in Table 6.3.1. Oracle RDBMS has a higher rating than Sybase (51 vs 35). Informix Online 6.0 does not support distributed disk mirroring. Open/Ingres does not support symmetric multiprocessing. P-X system/segment specification (3.2.5.3) requires 99% availability; therefore Informix and Open/Ingres were not benchmarked. Interbase was not benchmarked due to the market share (1%), and PROGRAM-X system/segment specification (3.5.2) requires that the 10 years lifecycle support maintenance and operation be met.
Table 6.3.1
| Evaluation criteria | Oracle 7.0 | Sybase System 10 | Informix Online 6.0 | Open/Ingres | Interbase 3.3 |
|---|---|---|---|---|---|
| High availability | 9 | 8 | |||
| Vendor stability | 8 | 4 | |||
| Support record | 4 | 3 | |||
| Portability from C1X DBs | 7 | 4 | |||
| Interface friendliness | 8 | 6 | |||
| Access security/integrity | 8 | 3 | |||
| User programming | 7 | 7 | |||
| Total | 51 | 35 |
Notes: (1) Score category is a scale from 1 through 10; 1 being lowest, 10 being highest. (2) Total is sum of all scores; higher score is better.
RDBMS Conclusion
This section concludes the relational database management systems trade study. The Oracle relational database management system satisfies best for the specified P-X DB functional and technical design requirements. The total score for Oracle was the highest; therefore, Oracle will be procured for developing the P-X DB. There are no other uncompleted trade studies that could affect the outcome of this conclusion.
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