Principles of database systems (I)-basic concepts of database systems and concepts of Database Systems

Principles of database systems (I)-basic concepts of database systems and concepts of Database Systems

Concept Model:

(1) express the overall logical structure of the data, which is a comprehensive description of the data involved in the entire application project by the System user. (Overall)

(2) modeling data from the perspective of user needs. (Viewpoint)

(3) independent from hardware and software. (Independence)

(4) It is a tool for communication between database designers and users. (Tools)

Logical Model:

(1) express the overall logical structure of the database, which is a full description of the Database of the entire application project by the designer. (Overall)

(2) modeling data from the perspective of database implementation. (Viewpoint)

(3) independent from hardware, but dependent on software. (Independence)

(4) It is a tool for communication between database designers and application engineers. (Tools)

External Model:

(1) It is a logical subset of the logical model. (Whole view standalone)

(2) independent from hardware and dependent on software. (Independence)

(3) reflects users' views on using databases. (Viewpoint)

Contact:

At first glance, several models seem different, but they all have four features: integrity, viewpoint, tool, and independence.

Summary:

When you feel "unable to understand", continue to look down. You can only find the connection between them after you look down. Do not stick to a specific detail. Those who are not looking for the whole world are not looking for a domain... grasp the macro view, look for contacts, and knit knowledge networks to make the knowledge in your mind more systematic ~~

Knowledge points of database system principles

Highlights and difficulties of the course
1. The basic concepts commonly used in the database, the characteristics of the database system, the operation process of the database system, the representation of the object-contact model (E-R diagram), the design of the object-contact database model.
2. Basic concepts of relational models: relational algebra and tuples relational calculus are used to express query requirements, and domain relational calculus is used to express query requirements.
3. use SQL statements to define basic tables, create indexes, Express Single-table queries, and join queries, express queries involving sorting of query results and grouping, and express data updates using SQL statements, use SQL statements to express nested queries and define views and query views.
4. Optimize the query expression using the Equivalent Conversion rule of relational algebra.
5.1concept of NF paradigm; Concept of function dependency, code and external code; concept of primary and non-primary attributes; Concept of partial function dependency and transfer function dependency. The concept of multi-value function dependency. Use the canonicalized method to break down a relational pattern into several patterns belonging to the 2NF, 3NF, and BCNF paradigms. An Algorithm for Solving Attribute Set closure, link code, and minimum function dependency.
6. database Design Features, methods and basic steps, using data flow diagram and data dictionary to describe user requirements, conceptual structure design and logical structure design method, E-R diagram to the Relationship Model conversion, database application system design.
7. Basic concepts of transactions and types of database system faults, implementation technologies of database recovery and database recovery strategies.
8. data inconsistency caused by concurrent operations. Use the three-level blocking protocol to solve the data inconsistency problem in concurrent operations, and use the two-segment lock protocol to ensure serializable concurrent operations.
9. Basic concepts of computer security, several database security control technologies.
10. Basic concepts of database integrity and three functions of the database integrity control mechanism.
11. Basic concepts of object-oriented databases, basic concepts of object-oriented relational databases, and connection and difference between object-oriented databases and Object-based relational databases.
12. Basic concepts of distributed databases, basic concepts of parallel databases, basic concepts of multimedia databases, basic concepts of spatial databases, basic concepts of network databases, and basic concepts of data warehouses.

Questions about the principles and technologies of database systems and multimedia technologies of Computer Science and Technology Majors over the years

Course syllabus of database Principles and Applications 1. course content and assessment objectives Chapter 1 Basic concepts of database system 1. the development stage of the Database Management Technology reaches the "memorization" level 1.1 manual management stage 1.2 file system stage 1.3 database Stage 2. data Description and data abstraction, achieve "Understanding" level 2.1 conceptual design, logical design, physical design data description 2.2 Data Link Description 2.3 conceptual model, logical model, external model, internal model data abstraction 2.4 three-layer model and two-level image 2.5 Data independence 3. database management system and database system, achieving "Understanding" level 3.1 working mode of Database Management System 3.2 main functions of database management system 3.3 composition of database system Chapter 2nd basis of Relational Database Design 1. database system design stage, reaching the "memorization" layer 1.1 Planning stage 1.2 requirement analysis stage 1.3 concept design stage 1.4 Logic Design Stage 1.5 physical design stage 1.6 database implementation stage 1.7 database operation and maintenance stage 2. the basic concept of a relational model reaches the "Understanding" level. 2.1 the basic terms of a relational model. 2.2 the definition and nature of a relational model. 2.3 three types of integrity rules. 3. the basic concept of object contact model reaches the "Understanding" level. 3.1 basic elements of the object contact model. 3.2 attribute classification. 3.3 Association design. 3.4 weak entities, subclass entities, and super class entities. 4. basic Design of the object contact model, reach the "comprehensive application" level 4.1 simple operation of the object contact model 4.2 using the concept design steps of the ER Model 4.3 ER model to the Relationship Model conversion rules 4.4 using the ER Model logical design step 5. instance analysis of the object contact model, reach the "simple application" level 5.1 ER Model of the inventory management system 5.2 ER Model of the personnel management system 5.3 ER Model of the hospitalization Management System 5.4 ER Model of the company's fleet management system Chapter 2 Relationship Model Design theoretical Basis 1. the design principles of the Relationship Model reach the "Understanding" level. 1.1 redundancy of the Relationship Model and exceptions. 1.2 four non-formal design principles of the relationship model. 2. function dependencies and codes, reaching the "Understanding" level 2.1 Definition of function dependencies 2.2 Relationship between function dependencies and codes 2.3 function dependency set and closure of Attribute Set 2.4 Minimum function dependency set 3. decomposition of paradigm and relationship model, reach the "simple application" level 3.1 Definition of 1NF 3.2 Definition of 2NF 3.3 definition of 3NF 3.4 Definition of BCNF 3.5 normalization concept of Relationship patterns 3.6 principles of Relationship Pattern decomposition 3.7 Standardization of 1 NF to BCNF design chapter 1 SQL language and relational algebra operations 1. relational algebra, which reaches the "simple application" level 1.1 five basic operations of relational algebra 1.2 four combinations of relational algebra 1.3 two expansion operations of relational algebra 2. the basic concept of SQL is as follows: 2.1 SQL database architecture 2.2 SQL composition 2.3 SQL characteristics 3. SQL data definition operations, achieve the "simple application" level 3.1 SQL basic data type 3.2 mode to create and cancel 3.3 basic table creation, modification and revocation 3.4 index creation and revocation 4. SQL data query operations, reaching the "comprehensive application" level 4.1 basic structure of query statements 4.2 simple query 4.3 connection query 4.4 nested query 5. the SQL data update operation reaches the "comprehensive application" level. The 5.1 insert operation is performed. The 5.2 delete operation is performed. The 6 modify operation is performed. SQL data view operations, to achieve the "comprehensive application" level 6.1 view creation and revocation 6.2 view update operations chapter 5th Database Management 1. the basic concept of transactions reaches the "recognition" level. 1.1 The definition of transactions. 1.2 the four properties of transactions. 2. database recovery reaches the "Understanding" level 2.1 recovery policy 2.2 fault type and Recovery Method 2.3 checkpoint Technology 3. the concurrency control of the database reaches the "Understanding" level. The three problems brought about by 3.1 of concurrent operations: 3.2 blocking type and Protocol 3.3 serializable concurrency scheduling 4 ...... remaining full text>