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Database Design Week 10
Create Tables • For the tables for the sample in the Wk10_TableInstanceChart.xlsx
Common Data Types in Access • Autonumber • Text • Memo • Number • Currency • Date/Time • Yes/No
Autonumber • Use for unique sequentialnumbering • Commonly used for PK (Primary Key) • Increments by 1 • Automatically inserted when a recordisadded.
Text • Used for text or combinations of text and numbers, such as addresses, or for numbers that do not require calculations, such as phone numbers, part numbers, or postal codes. • Stores up to 255 characters.
Memo • Use for lengthy text and numbers, such as notes or descriptions. • Should be used “sparingly”, because it takes up too much room in database • Stores up to 65,536characters (if not more)
Number • Use for data to be included in mathematical calculations, except calculations involving money (use “Currency”type). • When you are creating a RELATIONSHIP with an “AUTOnumber” field with the “PARENT” table
Yes/No • Use for data that can be only 1of 2 possible values, such as • Yes/No, • True/False, • On/Off. • Nullvalues are NOTallowed
Rule • One chart completed for each table • Wk10_TableInstanceChart.xlsx
Review Relationship Essentials • Need a primary key • EVERY TABLE NEEDS A PRIMARY KEY • Should be 1stfield • Need a foreign key • a Foreign Key is a column in a table used to reference a Primary Key in anothertable. • A table does NOT necessarily have to have a Foreign Key • Whenever you see: “MANY”—this will be the Foreign Key • Primary key and foreign keys are essential when you create relationships that join together multiple tables in a database
Build Time • For each of the following scenarios: • Create and write out a business narrative • Create list of ENTITIES/tables • Create the attributes for the table • Create the ERD and the relationship rules • Create a table instance chart
Table Design View • Exercise: • Create table for gender
Datasheet View • Exercise: • Add data to the gender table
Table Design View • Exercise: • Create Ribbon > Table Design in the Tables grouping • Identify your own PK • Moving the order of the rows
Create Table with Lookups • Exercise: • Add data to the city entity using a look up wizard as the data type for the province
Add Data to an Entity • Based on another entity • Exercise: • Create the students table (studentID, fname, lname and gender fields only)
Edit an Entity • Exercise: • Complete the Students table • Go back and look at your default value (note it was not added to previous records entered)
Edit Data in Datasheet View • Exercise: • Go back and add the age group and city for each of the students previously entered • Datasheet view • Record count • Add a new record • Search for a record • Sort the records
COMPACTING & REPAIRING A DATABASE • DATABASE TOOLS> COMPACT & REPAIR button • •As you add, edit, & delete objects, a database changes in size • •To minimize the size of a database & improve performance should be done on a regular basis • •Rearranges how a fragmented database is stored on disk
Want More Information • Visit the following site. http://www.functionx.com/access/index.htm
QUERIES: DEFINITION Is a QUESTIONto the database-asking for a “set of records”from 1or more Tables/QueriesMS Access responds by displaying the requested datais a storedquestion, rather than a stored responseresultsautomatically update,IFtable is edited, it allows you to view & operate on “selected subsets” of your data
Single Table Queries • Select fields to display • Sort by? • Simple Conditions • When you enter text into the criteria cell your text should be enclosed in quotes ("") to distinguish it from other expressions and operators that you may need to add.
Hybrid / Homework • Read Calculating in Access Queries • Read Calculating Totals in Access • Read Working out Someone’s Age • Watch Multi-Table Queries Part 1 & 2 • Database Assignment Part 2
HYBRID: MYITLABHYBRID: MYITLAB • MYITLAB HOMEWORK: