chapter 1 – introduction to access akhila kondai september 30, 2013
DESCRIPTION
BUT REALLY WHAT IS A DATABASE? Databases are used in real life, most of you use them without realizing it –WVU Directory – uses databases –Facebook – uses databases –MySpace – uses databases And many moreTRANSCRIPT
INTRODUCTION TO DATABASES
• A computer database is a structured collection of records or data that is stored in a computer system.
• A database relies upon software to organize the storage of the data and to enable a person or program to extract desired information.
• The term "database" refers to the collection of related records, and the software should be referred to as the database management system (DBMS); this is sometimes shortened to database manager or database system.
BUT REALLY WHAT IS A DATABASE?
• Databases are used in real life, most of you use them without realizing it
– WVU Directory – uses databases
– Facebook – uses databases
– MySpace – uses databases
And many more
AN EXAMPLE • Let’s look at the WVU Directory page.
What you see is sometimes called a form – it is nothing more than a friendly front end interface.
Say we want to search for all students named James Smith
When you hit search it will run a query that looks like this:
SELECT * FROM StudentsWHERE (((Students.FirstName)="John") AND ((Students.LastName)="Smith"))
AN EXAMPLE – ISOLATING RESULTS
• WVU has a database somewhere that lists all students, when we do a search we search that database for all students who have a first name James AND a last name Smith.
• We could either get exactly one result, no results or multiple results.
• This brings up the question, how do we differentiate between the James Smith that is a History major and the James Smith that is a Radiology major in our database?
• One way could be to use email addresses, since we hope everyone has a “unique” email address. But, is there another “unique” identifier that separates one person from another?
AN EXAMPLE – SIMPLE DATABASE
• In this example we can see why using last name as a “unique” way to identify students maybe a bad idea.
• StudentID, FirstName, LastName, Major, Email are called Fields. Each entry is called a Record, a collection of records make up a Table. A collection of tables make up a database.
• The Field StudentID has a special name called Primary Key since it uniquely identifies each student, no two students can have the same StudentID.
Student ID FirstName LastName Major Email
A123 John Smith Math [email protected]
B122 Jane Smith Finance [email protected]
WHAT IS ACCESS?
• “Is a relational database management system from Microsoft which combines the relational Microsoft Jet Database Engine with a graphical user interface.”
• Access is NOT a database – it is a database management system. There are numerous other database management systems.
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ACCESS VS EXCELWhen to use Access?• When you need a relational database to store your data or
you anticipate adding more tables.• When you have a large amount of data• Rely on external databases to derive and analyze the data
you need• Need to maintain constant connectivity to an external
database• Need to regroup data from different tables in a single place
with complex queries• Have many people working in the database and need strong
options to update the data
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ACCESS VS EXCEL
When to use Excel?• Require a flat or non relational view of your data• Want to run calculations or statistical comparisons on
your data• Know your data set is manageable (no more than 15,000
rows)
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THE HOME TABHOME Tab – the basic Access tab. Contains basic
editing functions such as cut and paste along with most formatting actions. ViewsClipboardFontRich TextRecordsSort & FilterFind
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THE CREATE TAB
CREATE Tab – Brings together all create operations in one area. Includes ability to create queries through the wizard or in Design view.
TablesFormsReportsOther
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THE EXTERNAL DATA TAB
EXTERNAL DATA Tab – Contains all operations to facilitate collaborations and data exchange.
ImportExportCollect DataSharePoint Lists
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THE DATABASE TOOLS TABDATABASE TOOLS Tab – The area that contains the
operational backbone of Access. Here you create and maintain relationships of the database. You also analyze the file performance and perform routine maintanance.MacroShow/HideAnalyzeMove DataDatabase Tools
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BASIC ELEMENTS OF A DATABASE
Field – is a basic entry or a data element, such as the name of a book or the telephone number. A field that uniquely identifies a record is called a Primary Key.
Record – is a complete set of all of the data (fields) pertaining to one person, place, etc
Table – is a collection of records, every table contains the same fields in the same order
Database – consists of one or more tables and the supporting objects used to get data from those tables.
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ACCESS TABLE EXAMPLEFields
Records
COMPARING ACCESS TO EXCEL
A FIELD in Access is equivalent to a COLUMN NAME in Excel
A RECORD in Access is equivalent to a ROW in Excel
A TABLE in Access is equivalent to a WORKSHEET in Excel
A DATABASE in Access is equivalent to a WORKBOOK in Excel
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Questions ?