hw1 110590049
tags db database
1.
install steps
commands
2. main characteristies
- Self-describing:
A DBMS catalog stores the description of a particular database (e.g. data structures, types, and constraints) - Insulation between programs and data:
program-data independence
3.a data model
Set of concepts to describe the structure of a database, the operations for manipulating these structures, and certain constraints that the database should obey.
3.b database schema
The description of a database. Includes descriptions of the database structure, data types, and the constraints on the database.
4.Three-Schema Architecture
- Internal schema: at the internal level to describe physical storage structures and access paths
- Conceptual schema: at the conceptual level to describe the structure and constraints for the whole database for a community of users.
5.For the binary relationships below,suggest cardinality ratios based on common-sense meaning of the entity types. Clearly state any assumptions you make
| Entity1 | Cardinality Ratio | Entity2 | Reason |
|---|---|---|---|
| Student | 1:N | Book | A book can only be own by one person at the same time. |
| Student | N:1 | Advisor | One advisor can have multiple students, but a student can only be connected to one advisor at a time. |
| ClassRoom | N:M | Wall | Walls can be shared by multiple classrooms, and a class can have multiple walls. |
| Student | N:M | Course | Reason: Students can be enrolled in multiple courses, and a course can have multiple students at the same time. |
| Car | 1:1 | Engine | One car should only have one engine at a time. |
6.a
| Entity1 | Cardinality Ratio | Entity2 | Reason |
|---|---|---|---|
| Student ID No. | 1:1 | ID No. | one person only have one ID number |
| Student ID No. | 1:1 | Name | one student only have one name |
| Student ID No. | 1:1 | Cellphone | one student only have one phone |
| Student ID No. | 1:1 | Signature | one student only have one signature |
| Student ID No. | 1:N | No. | one student can have multiple suspension |
| No. | 1:1 | Class | only suspension one class at time |
| No. | 1:1 | Date of application | one form only have one application time |
| No. | 1:1 | Date of Resumption | one form only have one resumption time |
| No. | 1:1 | Application | one form can only have one type of application |
| No. | 1:1 | Department/Graduate Institute | one form can only have one Department or Graduate Institues |
| No. | 1:1 | Reason for Suspension | one form only have one reason of suspension |
| No. | 1:1 | Suspension | one form only have one status of suspenstion |
| No. | 1:1 | Sigend by Parent | one form only have one signed |
| No. | 1:1 | Address | one form only have one address |
6.b
