Term
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Definition
| predicting what will happen under certain circumstances and preventing problems before they happen. |
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Term
| What are the two phases of database design? |
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Definition
(1) information level
(2) physical level design |
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Term
| What happens in the information level phase of database design? |
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Definition
| user requirements are gathered and a logical structure is designed to meet these requirements |
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Term
| Requirements might include what? |
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Definition
(1) reports
(2) queries
(3) transactions
(4) constraints |
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Term
| What will the result of the information level design include? |
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Definition
(1) entities
(2) attributes
(3) keys
(4) relationships between entities |
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Term
| This relationship between entities is often shown as what? |
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Definition
| E-R diagrams (entity-relation diagrams) |
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Term
| What is physical level design concerned with? |
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Definition
| the "physical" parameters of the system size, speed, cost |
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Term
| For physical level design, need to know what? |
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Definition
(1) size of tables
(2) frequency of different requirements
(3) expected response times |
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Term
| For each user, or a particular group, report, or transaction (this is for diagram in notes), what do you need to do? |
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Definition
(1) represent the user view as a collection of tables
(2) normalize the tables
(3) represent all keys
(4) merge with design from previous users |
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Term
| What are some keys that can be represented in step 3 for each user? |
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Definition
(1) primary
(2) candidate (alternate keys)
(3) foreign keys and what tables they represent (update and deletion strategies) |
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Term
| What is referential integrity by using example (rep --> cust) with foreign key Repnum --> cust? |
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Definition
| repnum must match an existing repnum in table rep or be null |
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