Presented By: Gail Rose-Innes Camps Bay High School ICT & CAT Department Microsoft Access 2010.
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Transcript of Presented By: Gail Rose-Innes Camps Bay High School ICT & CAT Department Microsoft Access 2010.
raw factsIt has no contextIt is just numbers and text
Data is raw, unorganized facts that need to be processed. Data can be seen as simple, random and useless until it is
processed and organized into information.
What is Information?data with contextprocessed datavalue-added to data
› summarised› organised› analysed
When data is processed, organized, structured or presented in a given context, so as to make it useful, it
is called Information.
Data 6.34 6.45 6.39 6.62 6.57 6.64 6.71 6.82 7.12 7.06
SIRIUS SATELLITE RADIO INC.
$5.80
$6.00
$6.20
$6.40
$6.60
$6.80
$7.00
$7.20
1 2 3 4 5 6 7 8 9 10
Last 10 Days
Sto
ck P
rice
Information
Data
Information
Summarizing the data
Averaging the data
Selecting part of the data
Graphing the data
Adding context
Adding value
your personal address book in a Word document . a collection of Word documents . a collection of Excel Spreadsheets . data collected, maintained, and used in airline reservation.
A Database is an Organized Collection of Information .
» An object comprised of fields (columns) » that collect records (rows of data) about a specific topic.
Table
Field» A table’s column that stores specific information and when combined
with other fields (columns), makes up a record.
Record» A row in a table that is a collection of related data.
QueryYou can locate specific information stored in a table, or in multiple
tables, by creating a query that specifies the criteria you want to match.
Queries can be:simple (looking for a certain criteria in one field), or complex (looking for multiple criteria in many fields).
FormsTo make entering data easier, forms are used.
Forms are user friendly; can prompt, offer dropdown boxes and validate the data entered by the users.
ReportsTables and query results appear in plain datasheets,
which are not very attractive when printed.
Reports present data from tables and queries in an attractive, customizable format — complete with titles,
headers and footers, and even logos and graphics.
Tables store data
Queries Organize or search for a specific data
Forms Display data on screen
Reports Print out data
Each field is defined by a data type.
Each data type takes up a specific space in the computer’s memory, some of these sizes can be changed & some of them
are fixed.
The following table shows the changes you can make to: Text, Number, & AutoNumber fields.
We should save disk space, especially in large databases, by defining the appropriate data type and adjusting the field size.
Data Types in Access
Data Type Used for Notes
Text Text & numbers General-purpose field containing any data. Limit of 255 characters. Cannot be used for numeric calculations. Use this type for numeric entries that will not have calculations performed on them, such as telephone numbers and ZIP codes.
Memo Text & numbers Limit of 65,535 characters. In Access 2007 file format, can hold rich text with formatting. Some limitations on usage in formulas & functions.
Number Numbers only Flexible field size of 1, 2, 4, 8, or 16 bytes. Can also hold symbols used as helpers for numbers, such as decimal points and commas.
Date/Time Numbers representing dates & times
Stores dates & times as 8-byte numbers. Only numbers representing valid dates or times are accepted.
Currency Numbers representing currency values
Stores currency values as 8-byte numbers. Even though the field might only show two decimal places, depending on formatting, it keeps track of up to four, to prevent rounding off.
Data types in Access
Data Type Used for Notes
AutoNumber
Automatically generating numbering for each record
Stores Access-generated values as 4-byte numbers.
Yes/No Boolean data -1 represent Yes and 0 represent No, but the field can be formatted to display values as True/False, On/Off, or Yes/No.
Hyperlink A text address representing an external source
You can link to Web sites, email addresses, files on your PC, files on a LAN, or virtually any other location.
Attachment Any supported file type Works only in Access 2007 databases. You can attach data files form word-processing programs, spreadsheets, and graphics editing programs, and so on.
Lookup Wizard Varies Depending on usage, either creates a lookup list from data that you specify of creates a lookup list from the values in another table. Can also be used to set up multivalued lists.