1. 1 CSE 2337 Introduction to Data Management Access Book – Ch 1

2. 2 DB Design Process: Discovery Phase

3. 3 Discovering and Evaluating Sources of Existing Data Identify information that organization needs to manage and organize Might begin to see patterns that indicate how to organize data Database management system (DBMS) –Includes: Oracle Microsoft Access MySQL

4. 4 One Goal Reduce Data Duplication and Redundancy.

5. 5 Considering Different Types of Data

6. 6 The Text and Memo Data Types Text data type –Letters and numbers –Not used in calculations or formulas –Stores maximum of 255 characters –Default for all fields created in access database Memo data type –Store long passages of text –Stores maximum of 65,535 characters

7. 7 The Number Data Type Stores both positive and negative numbers Contains up to 15 digits Use for values used in calculations

8. 8 AutoNumber Unique to Access Number automatically generated by access Produces unique values for each record Useful to distinguish two records that share identical information Produces values of up to nine digits

9. 9 Selecting the Correct Data Type Helps store correct data in correct format while using least amount of space Eases data entry and interactivity with data Choosing certain data types results in user-friendly interactive features –Drop-down menus –Check boxes –Hyperlinks Correctly manipulate data

10. 10 Assigning the Correct Field Size for Text Fields Important to consider field size when assigning data types –Minimize space reserved for each record by assigning smallest data type that will store data Be conservative when assigning field sizes –But not too conservative

11. 11 Assigning the Correct Field Size for Number Fields

12. 12 Naming Conventions Database tables must –Have unique names –Follow established naming conventions General rules for naming objects –Object names cannot exceed 64 characters –Object names cannot include period, exclamation point, accent grave, or brackets –Object names should not include spaces –Most developers capitalize first letter of each word when table name includes two words

13. 13 Leszynski/Reddick Naming Conventions I don’t particularly care!!!

14. 14 Understanding Relational Database Objects Users can view data in tables by: –Opening table –Creating other objects Four main objects in database –Tables –Queries –Forms –Reports

15. 15 Tables Data in relational database stored in one or more tables View data in table –Open it and scroll through records

16. 16 Queries Query –Question asked about data stored in database Query results –Look similar to table –Fields displayed in columns –Records displayed in rows

17. 17 Forms Used to view add delete, update and print records in database Based on table or query Interface more attractive than table datasheet Customize form’s appearance with instructions and command buttons Switchboard –Form displayed when database opened –Provides controlled method for users to open objects in database

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19. 19 Reports Formatted presentation of data from table or query Created as printout or to be viewed on screen Data displayed by report usually based on query Dynamic –Reflect latest data from object Cannot be used to modify data

20. 20 Creating Table Relationships Take advantage of interrelated objects Goal in good database design –Create separate tables for each entity –Ensure each table has primary key –Use common field to relate tables Relate two (or more) tables –Query them as though they are one big table Join –Specifies relationship between tables and properties of relationship

21. 21 One-to-Many Relationships Abbreviated as 1:M One record in first table matches zero one or many records in related table Primary table –One side Related table –Many side

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23. 23 One – to - one Abbreviated as 1:1 Exists when each record in one table matches exactly one record in related table

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25. 25 Understanding Referential Integrity Null value –Field does not contain any value Entity integrity –Guarantee that there are no duplicate records in table –Each record unique –No primary key field contains null values Referential integrity –If foreign key in one table matches primary key in second table –Values in foreign key must match values in primary key

26. 26 Integrity When database does not enforce referential integrity –Problems occur that lead to inaccurate and inconsistent data Orphaned –No longer match between primary key in primary table and foreign keys in related table

27. 27 Integrity Errors