Database Knowledge Recall

1:3 Types of models

1. Conceptual model: Based on user's cognition, data and information are modeled for database design. E-r Graph shows OH

2. Logical model: Modeling data in the view of a computer system. Hierarchical, mesh, relational, object-oriented, object-relational models.

3. Physical model: How data is accessed.

Data model: structure, data manipulation, integrity constraint composition.

Two: SQL statements

Three: Design of database table

Four: Oh, yes.

1. Cache: Reduce the number of requests (Web cache, reduce the number of HTTP requests, read from the cache; Database cache: Level One, Level two Oh!) Reduce the number of database accesses)

Database Knowledge Recall