BCS Certificate in Data Management Essentials

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BCS Certificate in Data

Management Essentials

Sample Paper A

Marking Guidelines

You are allowed fifteen (15) minutes reading time before the

examination starts. You are not allowed to write anything during that reading time.

This is an open-book examination. This means that you can refer to written material in addition to the examination paper itself.

Attempt ALL questions. All questions are based on the same scenario.

There are 40 marks in total for this paper. The mark awarded for each separate question will be shown with the question text.

This paper must not be retained or removed from the examination venue. Any attempt to do so, will result in disqualification from this examination. Copying of this paper is expressly forbidden without the direct approval of BCS, The Chartered Institute for IT.

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SCENARIO

THE SLOWA GROUP

The SLOWA Group is a retail conglomerate that has quickly grown through a number of mergers and acquisitions. Their business is conducted both through stores and through mail order operations.

The original outlets – independent stores, small chains of stores, and mail order businesses – have retained their own identities, and, in effect, operate as separate businesses under the overall group umbrella.

The original outlets were all supported by a diverse range of information systems. None of the original outlets had a single information system; separate systems for purchasing, stock management, point of sale, payroll and general finance being commonplace. These diverse information systems have a number of databases based on different technology. The SLOWA Group board has approved two information systems related initiatives – the introduction of a new system to handle the placing of advertisements for the company’s extensive product range in the press, on television, and via other types of media; and the creation of a Central Data Management Unit to support the whole group.

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1 For the new system to handle the placing of advertisements, an advert, before creation, must be the sponsored by a business unit. That business unit then continues to own the advert throughout its life. An advert is concerned with one product type only, and may be placed in the press and/or on TV and/or other media types.

a) Draw a logical data model (diagram) to represent the entities and relationships (and the names of those relationships) for this new system. The model should show the mandatory/optional nature of the relationships. Any many-to-many relationships should be resolved.

[12 marks] Marking Guidelines

(Note: any standard Entity-Relationship notation is acceptable)

½ mark for each entity type (2½ marks)

½ mark per pair of relationship names to maximum of (1½ marks) ½ mark for correctly indicating optional or mandatory

at each relationship end (4 marks)

½ mark for correctly indicating cardinality at each

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b) Suggest primary keys and two significant attributes for two of the entities shown in the model.

Sample Result

½ mark for each primary key (1 mark) ½ mark for each additional attribute (2 marks)

c) Develop a formal data definition, containing at least 8 elements, for one of your attributes.

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2 The SLOWA Group senior management realises that obtaining cross function management information in their current environment of different technology supporting different business areas is slow, complex and expensive.

Two proposals have been suggested for solving this problem – a corporate database and a data warehouse system.

Briefly describe the advantages and disadvantages of: i) A corporate database,

ii) A data warehouse system,

as a solution to the SLOWA Group senior management’s problem.

The main advantage of a corporate database is that it will provide a single consistent and accurate source of information to all the component parts of the SLOWA Group. Additionally it will simplify the technical management of the systems by removing the existing project-specific database technology, leading to reduction in support costs and training requirements.

The introduction of a corporate database will, however, have a number of

disadvantages. The database provides a single point of failure – if the database fails, nobody will be able to work. Each user will be connected to the database by a

network, so reliance on the network is increased. Any network failure will affect some or all of the users. Because of the large number of users and the network traffic the performance under update may be unacceptable. Furthermore, a change project will be required to achieve a single corporate database.

The introduction of a data warehouse will provide a set of historical data for trend analysis to support strategic decision making. Because its historical data is

generated from copies of the data in operational systems, the introduction of the data warehouse will have a minimal impact on the existing SLOWA Group operational systems.

The data in the data warehouse will, however, never be up to date – the currency of the data will depend on the regularity of the sampling of the data in the operational systems. The collection of historical data in the data warehouse will be very large, so will need expensive specialist hardware. Also, specialist skills are required to design and implement a data warehouse.

Up to 3 marks for Corporate Database advantages Up to 3 marks for Corporate Database disadvantages Up to 3 marks for Data Warehouse advantages Up to 3 marks for Data Warehouse disadvantages

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3 The SLOWA Group Central Data Management Unit will develop a repository. What issues could arise in developing and populating such a repository?

The content of the repository (for example, data models, data definitions, validation rules, and mappings between logical data models and physical implementations) needs to be identified.

A method of handling synonyms (or aliases) and homonyms needs to be developed.

A decision will need to be made as to whether this is to be single, centralised repository or whether the repository is to be distributed across the SLOWA Group business areas.

An approach to version control needs to be identified. (Other plausible answers are acceptable)

1 mark for each valid suggestion up to a maximum of 4 marks

4 Although the SLOWA Group senior management have decided to set up a central data management group, they have limited the staffing of this group to only two employees. What combinations of the data manager, data administrator, repository administrator and database administrator roles would you recommend for each of these two employees? You can assume that the employees will have the relevant experience for the combinations you suggest. No more than two roles per employee can be suggested. Briefly justify your allocation of roles to employees.

Possible combinations are as follows: First Employee:

Roles:

Data Manager and Data Administrator Justification:

These are both 'business-oriented' roles, requiring both knowledge of the SLOWA Group business ethos and processes and the ability to

communicate with business people at all levels. These are also both 'policy making' roles.

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Second Employee: Roles:

Database Administrator and Repository Administrator Justification:

These are both 'technical' roles, involving the management of software (both DBMS and repository software). Both roles are involved with the technical implementation of data management policies.

1 mark for specifying the split of the roles

Up to 2 marks for each justification (i.e. a maximum of 4 marks)