Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
INFO MANAGEMENT L6
Advanced Data Modeling
| Question | Answer |
|---|---|
| is the process of creating more detailed and accurate database models that represent complex real-world situations. | Advanced Data Modeling |
| a general entity related to one or more entity subtypes, that contains common characteristics. | Supertype |
| a specialized version of the supertype that contains unique characteristics of each entity subtype. | Subtype |
| depicts the arrangement of supertypes and subtypes via the “IS-A” approach. | Specialization |
| enables subtypes to inherit attributes and relationships of supertypes. all entity subtypes inherit their primary key from the supertype | Inheritance |
| is the most important attribute of an entity because it uniquely identifies each record in a table. Think of it as an ID number for every row. A primary key can be a single attribute, a combination of attributes, or a system-generated value | Primary Key |
| Every value must be unique; no two records can share the same PK value. | Uniqueness |
| primary key cannot be empty (NULL) | Not Null |
| Primary keys and foreign keys work together to create relationships between tables | Works with FKs |
| Avoid intelligent or descriptive values | No Semantic Meaning |
| Changing PK values increases database workload and risks data inconsistency | Stable |
| Easier to use as a foreign key in other tables | Prefer a Single Attribute |
| Faster performance, Easier indexing, Can auto-increment (e.g., 1, 2, 3, 4...) | Prefer Numeric Values |
| Do NOT use sensitive data (Government IDs, Passport Numbers) | Security-Compliant |
| When to use Composite Primary Keys? | When used as identifiers of weak entities. - A weak entity cannot exist on its own; it needs a parent entity - The entity depends on another entity to exist |
| is an artificial key created by the system. | Surrogate Key |
| Selected candidate key has embedded semantic contents. | Surrogate Key |
| The selected candidate key is too long or heavy. | Surrogate Key |
| Design Case one record in Table A is related to one and only one record in Table B | Implementing 1:1 Relationships |
| Design Case Existing attribute values are replaced with new values without regard to the previous value. | Maintaining the History of Time-Variant Data |
| Design Case Happens when relationships are incomplete or improperly defined. Leads to incorrect query results | Fan Traps |
| Design Case Storing the same relationship or data in multiple places. | Redundant Relationships |
Created by:
user-1782765