Database collection of related information stored in an organized form Database program software tool for storage & retrieval of that information.

Data is held in tables Record: one row in a a table Field: columns that each record is divided into Filing cabinet analogy Database Table Record Field (ABC Inc.) (Customers) (cust#78) (last name) Database Terminology

EMPLOYEE TABLE Last First Work Id Name Name Station 001 Smith Joan A 002 Jones Paul A 003 Doe John B 004 Black Jason A WORK STATION TABLE Work Make and Operating Station Model System A IBM-153 MS B DELL-A14 Linux A IBM-153 MS A HP-A919 MS EMPLOYEEWORK STATION 11 Relational Database one-to-one relationship table record key each employee has one workstation

DEPARTMENT TABLE Id Name AR Accounts Receivable IT Information Technology HR Human Resources MF Manufacturing EMPLOYEEDEPARTMENT *1 Relational Database one-to-many relationship EMPLOYEE TABLE Last First Id Name Name Department 001 Smith Joan IT 002 Jones Paul MF 003 Doe John IT 004 Black Jason HR key a department has many employees an employee works in one department

Relational Database many-to-many relationship STUDENT TABLE Last First Id Name Name 001 Green Jack 002 Black Millie 003 Taylor Peter 004 Trane Oscar COURSE TABLE Id Name ASTB03 Astronomy CSCA02 The Why and How... CSCA48 Programming MTGA04 Management ENROLMENT TABLE Student Course 001 CSCA MTGA CSCA CSCA STUDENTCOURSE * 1 ENROLMENT * 1 key a course has many students a student takes many courses

Flat vs Relational Flat database system that performs operations on a single file Relational database system that has a number of different tables, which may be linked together by common fields

Flat Suppose you want to store information about books and their authors 1 st Solution:

both solutions: replication & data accuracy problems, wastes space, data retrieval problems Flat 2nd Solution:

Correct solution uses 2 linked tables author’s name common to both tables one-to-many relationship Relational ∞ 1

Primary Key Every table should have a primary key –must be unique –prevents duplicates –maintains sort order (table index) –used to define relationships –may be a combination of several fields GoodBad SINLast Name Employee IDAddress Account #Dept ID User IDJob Title any item that could be duplicated

RecordField value Database Terminology this is an Access Table:

primary key (every table needs one) is used for sorting the table accessing individual records linking tables

Form for entering records into a Table

example of a Query on one Table

similar Query but showing only failing marks

similar Query, now modified to include name and address from another Table

example of a Report based on a Table

example of a Report based on a Query

MS Access Environment Database Window Menu Bar Toolbar Object Buttons tables wizards Status Bar

Using Table Wizard Designing a table yourself (using Design view)  field names  data types  primary key  properties Views: Datasheet or Design  enter data using the Datasheet view Creating a Table

Design View Primary Key Field Properties Data Type Description Field Names

Data Types Text Memo Number Date/Time Currency AutoNumber Yes/No OLE Object Hyperlink

Properties Field size Format Input Mask Caption Default Value Validation Rule Validation Text Required Allow Zero Length Indexed

Currently selected record: editing  saved Datasheet View Use to add, edit, or delete records Total records Number of current record End

Relationships  Create a 1-to-many relationship between the CustomerID fields Tools  Relationships…

Relationships  a CustomerID can appear once in Customers and many times in Invoices  a CustomerID in Invoices must be in Customers One-To-Many relationship (Join)

Relationships Enforcing Referential Integrity causes an error message if a CustomerID not in the Customers table is entered

Indexes Examine indexes set up for database –make it faster to search a table –should be set up if searching on a field is anticipated Note: indexing refers to how data is stored, whereas sorting changes how the table is displayed.

Create a Form: wizard Form view

Form: Design view drag Toolbox sizing handles

Form: complex example Command Button Label Text Box (bound to field) Each page shows one record