Microsoft Access Intro Class 1 Database Concepts

2 Paper vs. Database With a paper filing system, you have to cross out, erase, or redo a record to make corrections. They also take up a lot of space. With an Access database, you have more room and can easily add, move, edit, find, and delete records. A little trivia: One 500 MB CD-ROM can hold the same data as 650,000 sheets of paper can hold.

3 Comparing Excel to Access FeatureExcelAccess LayoutProvides a natural tabular layout for easy data entry Provides a spreadsheet “view” as well as forms which arrange data in many ways StorageLimited to approximately 65, 000 records per sheet Able to store any number of records up to 2 gigabytes Linked tables Manages single lists of informationAllows links between lists of information to reduce data entry redundancy ReportingLimited to a spreadsheet printoutProvides sophisticated reporting features such as multiple headers and footers and calculations on groups of records SecurityVery limitedEach user can be given access to only the records and fields they need Multi-user capabilities Does not allow multiple users to simultaneously enter and update data Allows multiple users to simultaneously enter and update data Data entry screens Provides limited data entry screensProvides the ability to create extensive data entry screens called forms

4 Database Design Flat file database All data stored in a single table RDBMS Manages, stores, retrieves large amounts of information Reduces redundancy (duplication of data) by linking tables Good database design reduces redundancy by Normalizing the data

5 Introduction to Database Management Systems Database Management Systems (DBMS) Used to store, retrieve and order large amounts of information Access Stores all information in one file (up to 2GB file size) Is a relational database management system (RDBMS) Link tables through a common field Combine data in new objects and minimize data duplication

6 The Access 2003 Interface Database window toolbar Tables Queries Forms Reports Pages Macros Modules Groups Common to all databases

7 The Database Structure Table Foundation of the database Store your data Forms Data input View Records Reports Printing Presentations Queries Sort, search, limit data Perform calculations Macros Automate existing commands Modules Programming New commands

8 Microsoft Access Database Specifications AttributeMaximum Microsoft Access database (.mdb) file size Number of objects in a database Modules (including forms and reports with the HasModule property set to True) Number of characters in an object name Number of characters in a password Number of characters in a user name or group name Number of concurrent users 2 gigabytes minus the space needed for system objects. 32,768 1,

9 Getting Help Office Assistant Office Assistant – Ask him a question and get a list of possible solutions. Also access the Contents, Answer Wizard, and Index help text. What’s This? What’s This? – Learn more about a particular object in an Access window. Ask a Question Ask a Question – Get help without using the Office Assistant character Online Help Online Help – Access Microsoft’s Web page for more help.

10 Tables Made up of columns (called Fields) and rows (called Records) Provides a spreadsheet-like view Used to generate all the other objects in the database Table properties allow you to streamline the data entry process and validate data as it is entered Can switch between Datasheet View and Design View by clicking the View button or clicking the View menu.

11 Navigation Buttons The navigation buttons in a table or form work like the ones on a CD-player. First recordLast recordPrevious recordNext record

12 Keyboard Shortcuts Next fieldTab or right arrow key Previous fieldShift + Tab or left arrow key First field in record Home Last field in record End

13 Queries Used to Find records based on specific criteria Filter data Group data with totals Combine fields from multiple tables Update or delete data Append data Create a new table Query results are called a recordset Queries also have a Datasheet View and a Design View

14 Forms Used to display, edit and enter data on the screen More friendly user interface Data is linked back to source table Changes made to data in form are reflected in source table and vice versa To change structure or layout of form, switch to Design View

15 Reports Used to print records Based on a table, query or SQL statement Sorting and grouping Formatting Contain calculated expressions Contain headers and footers, page numbers etc.

16 Pages (Introduced in Access 2000) Data Access Pages can be published to the internet or intranet Live link to the data (data can be updated from anywhere) Macros Used with forms and reports to automate database operations Easy to learn Can be converted to VBA Slower and being phased out by Microsoft although still supported in Access XP Modules Small program written in VBA More flexible and powerful than a macro Better choice to automate applications, runs faster, allows trapping of errors Pages, Macros & Modules

17 Planning the Database The more time you spend planning a database, the less time you spend correcting bad structure, much like planning to build a house. A blueprint is a valuable tool. Take your time and plan it well.

18 Steps in Planning a Database Determine the purpose of the database and give it a meaningful name Determine what reports/queries you want the database to produce Collect the raw data that will be stored in the database Sketch the structure of each table, including fields, names and data types

19 Creating a Database in Access Click File menu, then click New… Choose where to save the database, then type a name for it Click the Create button

20 Creating a Table Using the Table Wizard In Database window, double-click the option to create a new table using a Wizard Follow the instructions on each screen of the wizard Warning: Wizard may make assumptions based on U.S. settings (e.g. Interprets Postal Code as Zip Code) Better to design table using Design View

21 Primary and Foreign Keys Primary Key Uniquely identifies a record in a table Data in table is sorted by primary key by default When entering records, cannot be left blank Composite key – primary key that consists of two or more fields Foreign Key The join field in the secondary table in the relationship

22 Choosing a Primary Key Good Choices Social Security Number Employee ID Number Account Number User ID Address Bad Choices Last Name Address Department ID Job Title Any item that could be duplicated A primary key field must be unique.

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