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【正文】 ent ? Normalization ? Process of streamlining plex groups of data to: ? Minimize redundant data elements ? Minimize awkward manytomany relationships ? Increase stability and flexibility ? Referential integrity rules (數(shù)據(jù)參照完整性規(guī)則） ? Used by relational databases to ensure that relationships between coupled tables remain consistent ? . When one table has a foreign key that points to another table, you may not add a record to the table with foreign key unless there is a corresponding record in the linked table Essentials of Business Information Systems Chapter 5 Foundations of Business Intelligence: Databases and Information Management 169。 2022 by Prentice Hall Sample Order Report Figure 54 The shaded areas show which data came from the SUPPLIER, LINE_ITEM, and ORDER tables. The database does not maintain data on Extended Price or Order Total because they can be derived from other data in the tables. The Database Approach to Data Management Essentials of Business Information Systems Chapter 5 Foundations of Business Intelligence: Databases and Information Management 169。 2022 by Prentice Hall The Final Database Design with Sample Records Figure 55 The final design of the database for suppliers, parts, and orders has four tables. The LINE_ITEM table is a join table that eliminates the manytomany relationship between ORDER and PART. The Database Approach to Data Management Essentials of Business Information Systems Chapter 5 Foundations of Business Intelligence: Databases and Information Management 169。 2022 by Prentice Hall EntityRelationship Diagram for the Database with Four Tables Figure 56 This diagram shows the relationship between the entities SUPPLIER, ART, LINE_ITEM, and ORDER. The Database Approach to Data Management Essentials of Business Information Systems Chapter 5 Foundations of Business Intelligence: Databases and Information Management 169。 2022 by Prentice Hall ? Specific type of software for creating, storing, anizing, and accessing data from a database ? Separates the logical and physical views of the data ? Logical view: How end users view data ? Physical view: How data are actually structured and anized ? Examples of DBMS: Microsoft Access, DB2, Oracle Database, Microsoft SQL Server, MYSQL DBMS Database Management Systems Essentials of Business Information Systems Chapter 5 Foundations of Business Intelligence: Databases and Information Management 169。 2022 by Prentice Hall Human Resources Database with Multiple Views Figure 57 A single human resources database provides many different views of data, depending on the information requirements of the user. Illustrated here are two possible views, one of interest to a benefits specialist and one of interest to a member of the pany’s payroll department. Essentials of Business Information Systems Chapter 5 Foundations of Business Intelligence: Databases and Information Management Database Management Systems 169。 2022 by Prentice Hall Operations of a Relational DBMS ? Select: ? Creates a subset of all records meeting stated criteria select * from SUPPLIER； select Supplier_Number, Supplier_Name from SUPPLIER。 select * from SUPPLIER where Supplier_Number = ‘8259’。 ? Delete: delete from SUPPLIER where Supplier_Number = ‘8259’。 ? Insert: insert into PART (Part_Number, Part_Name, Unit_Price, Supplier_Number) values (‘180’, ‘wheel’, ’’, ‘8259’)。 Dat
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