Conceptual database design
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The document discusses the need for databases and outlines some common problems with alternatives like spreadsheets. It then provides an overview of the database design process, including requirements modeling, building a conceptual data model with entities, attributes, and relationships, and then logical and physical database design. Key aspects of conceptual modeling are defined, such as identifying entity types and attributes, determining relationships and domains, and selecting primary keys. The modeling process is checked for redundancy and validated against user requirements.
Conceptual database design
- 1. Muhammad Umair Oracle Database 11g Developer Track
- 2. › To solve a problem – You have some data(information) of your client or your business you want to create. – There must be must be some data you want to store – And this data could be anything about customers, employee, products, dates, numeric from, document fine, images, audio/video etc. › But you can already store data – Write in a text file and type in your information – Use spreadsheet – If you got documents organize them in folder
- 3. › Many small business starts with spreadsheet – And work continue like this for years – And that might be causing no problem › Just having data is not good enough reason to have database – Having data is not the problem
- 5. › Problems – Size – Ease of update – Accuracy – Security – Redundancy – Importance
- 6. › Size
- 7. › Ease of update
- 8. › Accuracy
- 9. › Security
- 10. › Redundancy
- 11. › Importance
- 12. › You might have all of these problems or some of these problems › These are the reason we need database › These are the problems
- 13. › Requirements modeling (conceptual, pictures) – Decide what entities – should be part of the application – and how they should be linked.
- 14. › Conceptual Model – Merge the collective needs of all applications – Determine what Entities are being used › Some object about which information is to maintained – What are the Attributes of those entities? › Properties or characteristics of the entity › What attributes uniquely identify the entity – What are the Relationships between entities › How the entities interact with each other?
- 16. › Logical Model – How is each entity and relationship represented in the Data Model of the DBMS › Hierarchic? › Network? › Relational? › Object-Oriented?
- 17. › Determine user requirements › Determine business rules › Build conceptual data model – outcome is an entity-relationship diagram or similar communication tool Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance
- 18. › To build a conceptual data model of data requirements of enterprise – Model comprises entity types, relationship types, attributes and attribute domains, primary and alternate keys, and integrity constraints › Step 1 Identify entity types – To identify required entity types – Typically nouns, noun phrases, major objects
- 20. › Step 2 Identify relationship types – To identify important relationships that exist between entity types – Typically verbs, verb phrases – Determine multiplicity constraints
- 23. › Step 3 Identify and associate attributes with entity or relationship types – To associate attributes with appropriate entity or relationship types and document details of each attribute – Determine information required › Step 4 Determine attribute domains – To determine domains for attributes in data model and document details of each domain
- 25. › Step 5 Determine candidate, primary, and alternate key attributes – To identify candidate key(s) for each entity and if there is more than one candidate key, to choose one to be primary key and others as alternate keys – Strong entity › Primary key easily identifiable – Weak entity › Primary key not identifiable › Need to map entity & relationship to owner entity to identify primary key
- 27. › Step 6 Consider use of enhanced modeling concepts (optional step) – To consider use of enhanced modeling concepts, such as specialization / generalization, aggregation
- 29. › Check model for redundancy – To check for presence of any redundancy in model and to remove any that does exist
- 32. › Step 8 Validate conceptual model against user transactions – To ensure that conceptual model supports required transactions › Describe transactions › Use transaction pathways › Example – List the details of properties managed by a named member of staff at the branch
- 33. › Step 9 Review conceptual data model with user – To review conceptual data model with user to ensure that model is ‘true’ representation of data requirements of enterprise