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MS ACCESS 2010. What is Database?. A database is a collection of data that is organized so that its contents can easily be accessed , managed, and updated. EXAMPLES OF DATABASES. What is Access?. ACCESS is a relational database management system.
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What is Database? • A database is a collection of data that is organized so that its contents can easily be accessed, managed, and updated.
What is Access? • ACCESS is a relational database management system. • Relational databases allow you to organize your data into tables • Each table focuses on a specific topic; the various tables can then be linked to each other for inquiry and reporting purposes.
Database Objects
Database Objects • Microsoft Access uses four objects to create a Database: • Tables • Queries • Forms • Reports
Table • A table is the basic element of a Database and contains the data entered by users. • Each row (or record) contains information about a particular item (e.g., an employee). • The record is made up of several fields; each field contains one piece of information relating to the item (e.g., employee's name, address, phone, etc.).
Query • A query extracts selected data from a table (or another query) and presents it in spreadsheet format.
Form • A form is a graphical template based on a table (or query). • It is used to enter new data into the database or display existing data.
Report • A report extracts selected data from a table (or query) and formats it for printing.
What is a Table? • A table is a database object used to store, organize and view data. All other objects are based on the data stored in tables. • Tables are comprised of: • Fields - represented by columns • Records - stored as rows.
Text • Any character (alpha, special characters, numbers) • Up to 255 in length • Numbers cannot be used for calculations
Memo • Any character (alpha, special characters, numbers) • Up to 65,000 in length • Numbers cannot be used for calculations • Field cannot be sorted or indexed
Number • Numeric data to be used for mathematical calculations • Not to be used for currency fields • Field Size property further defines its function and size
Date/ time • Must be a valid date/time entry at entry time • Format property determines display format
Currency • Accepts monetary values with a dollar sign and decimal point. • It can be used for computations
Lookup • Creates a field that lets you look up a value from another table or from a list of values.
Attachment • Stores graphics, sound and other types of files attachments.
Hyperlinks • Stores a value that contains a hyperlink. • Clicking the value activates the link and opens a webpage or addresses a message to an email address.
Yes/No • Stores Yes/No, True/False or On/Off Values
Auto Number • Adds a unique numeric field value to each record in a table.
Calculated • Opens the Expression builder dialog box which lets you specify fields and operators to use in calculations.
Field Properties
Field Size • Sets a maximum size for data • Varies according to Data Type:
Input Mask • Controls the way data is entered; frequently used for telephone numbers, postal codes, SSN #’s, date/time fields. • ACCESS offers a Wizard for text and date/time data types.
Caption • You specify text for the label attached to a field; • Will be used as the column heading when displaying tables, queries and reports. • The default value is Field Name.
Default Value • Specifies a value that will be automatically entered when you create a new record.
Primary Key • The primary key of a relational table uniquely identifies each record in the table. • It can either be a normal attribute that is guaranteed to be unique (such as Social Security Number in a table with no more than one record per person.