PgP MIS 202 Access Overview 1 Microsoft Access Introduction to Relational Databases Powerful tool to collect and analyze business data, facilitates decision- making

PgP MIS 202 Access Overview1-2 Database Concepts-Databases  Relational Database-collection of related tables  Common Field-connect records in separate tables  Primary Key-field(s) uniquely identify record  Foreign Key-Primary Key from one table is Common Field in another table

PgP MIS 202 Access Overview1-3 Database Concepts-RDBMS  Relational database management system functions Create database structures Add and edit records Query capability (SQL) Report generator Data validation and protection Data sharing Ability to handle large amounts of data

PgP MIS 202 Access Overview1-4 Database Concepts-Tables  Field-single characteristic of a person, place, object, event or idea  Table-collection of fields that describe a person, place, object, event or idea  Field Value-specific field content  Record-set of field values

PgP MIS 202 Access Overview1-5 Database Objects-Queries  Select queries answer questions using data stored in a database  Action queries change database data  Query Wizard enables learning query creation

PgP MIS 202 Access Overview1-6 Database Objects-Forms  Allows you to maintain and view records in a database  Mainly for on-screen output  Form Wizard enables learning form creation

PgP MIS 202 Access Overview1-7 Database Objects-Reports  Allows you to view records in a database  More formatting flexibility and options than a form  Mainly for printed output  Report Wizard enables learning report creation

PgP MIS 202 Access Overview1-8 Database Administration  Compacting-delete unused objects, defragments the database  Backup-protect from data loss or damage  Restore-to make sure your backup scheme is working  Convert databases, link tables  Many other topics-journaling, rollback…

PgP MIS 202 Access Overview 9 Microsoft Access Database and Table Design Requires up front planning to create useful database

PgP MIS 202 Access Overview1-10 Designing Databases  Determine fields needed to produce information to make decisions (forms, reports)  Group fields by subject/topic into tables  Create primary key for tables  Determine and set field properties  Include common fields to link tables  Normalize to avoid data redundancy

PgP MIS 202 Access Overview1-11 Designing Tables  Tables are composed of fields, set field properties to accomplish your goal  Develop and use a field naming convention  Understand and set field data types  Decide on field size, be aware of storage and performance issues

PgP MIS 202 Access Overview1-12 Design Aids  Database and Table Wizards Learn typical field settings and properties by observing how Microsoft does it

PgP MIS 202 Access Overview1-13 Table Design View  Choose Field Name and Data Type Description appears in status bar, good to add  Choose Field Properties Properties vary by Data Type Common-Field Size, Required, Format

PgP MIS 202 Access Overview1-14 Table Design View  Choose Primary Key Indexed: Yes(No Duplicates) unique Indexed Fields speeds up searches but requires CPU cycles Entry required, no null values entity integrity

PgP MIS 202 Access Overview1-15 Table Datasheet View  Data Entry Be aware of left column symbols, navigation Data entry can also be done in forms File>Save does not save record, that is done when you move to another record

PgP MIS 202 Access Overview1-16 Table Modifications-Design  Be aware of ramifications  Possible Field actions: Delete Move Add Modify Properties

PgP MIS 202 Access Overview1-17 Table Modifications-Records  Possible actions: Copy(are field structures similar?) Open multiple copies of Access? Delete Modify Copy field value from previous record, Ctrl+’

PgP MIS 202 Access Overview1-18 Table Relationships  Defining and using table relationships is the way to combine related data  One to many Unique record from one table can have zero, one or many related records in another table

PgP MIS 202 Access Overview 19 Microsoft Access Query Basics Obtaining Answers to Data Questions Creating a query is easy, creating a query that does what the client or your co-worker wants is difficult.

PgP MIS 202 Access Overview1-20 Querying Databases  Filters-datasheet tools to temporarily display set of records Filter by Selection Filter by Form Advanced Filter

PgP MIS 202 Access Overview1-21 Querying Databases  Most common type- Select Query  Asks a question about the data stored in tables, only certain records meet the criteria and are selected

PgP MIS 202 Access Overview1-22 Querying Databases  Query, Design View Query By Example (QBE) is the Access user interface that creates Structure Query Languate (SQL) statements  Query, Datasheet View Display returned records, or ‘answers’ Can be different each time query is run, why?

PgP MIS 202 Access Overview1-23 Querying Databases  Creating queries is one of the most important skills in any database program  Queries are the basis for forms and reports  Good form and report design is a result of starting with a good query design

PgP MIS 202 Access Overview1-24 Querying Databases  Sorting, Ascending or Descending Up to 10 fields, done from left to right  Show check box- determines if field is displayed in datasheet Why needed? Set criteria for a field that you do not want displayed

PgP MIS 202 Access Overview1-25 Querying Databases  Specifying Record Selection Criteria- learning to return just the records you need  Learn to formulate expressions, used in: Query criteria and calculated fields

PgP MIS 202 Access Overview1-26 Querying Databases  Operators- key expression building tool Like, In, Between…And… =,, <>  Exact matches  Multiple criteria And-tends to return fewer records Or-tends to return more records

PgP MIS 202 Access Overview1-27 Querying Databases  Calculated Fields-derivable quantities that should not be stored (why?) in underlying table, such as: ExtendedPrice: Quantity * Price Age: DateDiff("yyyy",[DateOfBirth],Date())  Expression Builder-useful tool  Zoom Box (Shift+F2)

PgP MIS 202 Access Overview1-28 Querying Databases  Aggregate Functions-useful for gathering statistical information, watch “group by”

PgP MIS 202 Access Overview1-29 Querying Databases  Group By-use in conjunction with aggregate functions or alone Consolidate records into groups based on chosen fields  Useful in finding unique field values