First, Database Design Overview
Life Cycle Database
Database design goal:
- Meet the needs of the application function (deposit, withdraw, delete, change),
- Good performance database (shared savings, integrity, consistency, security of data access efficiency and space)
Content database design
The method of database design
- Intuitive Design (the most primitive database design method)
- Design Specification :( New Orleans Design Method : requirement analysis, conceptual design, logical structure design, physical structure design; Database Design Method Based ER ; design method based on a third paradigm , is a class structure design method)
- Computer Aided Design (aided software engineering tools)
Database design process
Second, the basic steps of database design
Needs analysis (database design starting point)
- Goals: information and application processing requirements of understanding and analysis of the user, and the results according to a certain format finishing needs analysis form.
- Role: This report is a follow-up analysis of the conceptual design, logical design, physical design, database construction and maintenance basis.
Step analysis needs:
- Range determination database (first database work)
- --- application process analysis to understand and analyze the relationship between the data and data processing
- Data collection and analysis
- Preparation of needs analysis
******************** range determination database (first database work) **************
(1) Effective use of computer equipment and the potential database system; (2) improve the resilience of the database; (3) avoid the application of too much or too large to do during the changes to the database; (4) extend the life cycle database .
******************** Application Process Analysis *************************** *****************
The results of analysis of the application process is an important basis for the design of the database structure
(1) which data is used; the sequence (2) data used; (3) where the policy for the data processing and handling and the results;
****************************** collection and analysis of data **************** ***************
Data collection and analysis task is to understand and analyze the composition of the data format and operating characteristics, and the semantic relationship of each data element, etc., and collect them together prepared for the archives.
Content analysis:
--- static structure is not applied thereto when the application operating status of the original data (data (static structure) refers to the application operating thereon without applying the original condition data, which may be performed by the data classification and data element table Description)
- Data classification: a general description of the data
- Table data elements: refers to the data item or property in common sense
--- dynamic structure is applied to the application operating condition data after the above data
- Classification tasks: a task refers to the relatively independent operations to serve a particular sequence processing function
- Operation data characteristics table: to describe the relationship between the tasks and data, which includes different frequencies of the different tasks performed operations on data
Specific requirements using the data of data constraints ---
- Security and confidentiality 1) data
- Integrity 2) data
- 3) Response time
- 4) Data Recovery
************************** writing requirements analysis ******************** *********
Conceptual design (concept model): independent of any software and hardware main objectives: to maximize meet the application requirements
- Entity analysis (top-down method)
- Attribute Synthetic method (bottom-up approach)
- Conceptual Model (top-down)
Logic Design Structure: target concept model into an equivalent, and the model data structure support for specific DBMS
Physical Design: specific tasks is determined primarily database storage structures and access methods on a storage device, depending DBMS may also include indexing and aggregation, as well as the physical block size, the number and size of the buffer, data compression selection, etc. .
Database Implementation:
- Load data (collection, classification, sorting, validation, input, etc.)
- Application Design
- Database test run: facilitate the work of personnel in and familiar with the system; avoid improper operation of man-made damage in favor of formal operation.
Database Operation and Maintenance: to ensure the normal operation of the database; system maintenance is the most difficult job database reorganization and reconstruction.
Third, relational database design methodology
