ist 220 – intro to databases lecture 2 touring microsoft access
TRANSCRIPT
IST 220 -- Intro To Databases 28/27/2002
Microsoft Access As A DBMS
Basic objects are provided to support common DBMS functionality
Multiple views are used to provide graphical interfaces to different users
User friendly graphical interfaces make define and implementation DB’s easy
Macros (and modules) facilitate convenient application capabilities
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Main Objects In Access
Table – defines and stores data Query – provides a custom view of data from one or
more tables Form – provides a convenient way to enter, display,
and/or print data Report – presents selected data in attractive fashion Page – formats selected data in HTML file so that is
can be displayed by a Web browser Macro – built-in functions that can be customized to automate
certain processes Modules – VBA code for further automation
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Objects & Their Relationships
Tables
Queries
DA Pages
Forms Reports
Macros
Trigger Trigger
Open/Filter Print/View/Filter
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Typical Usages
Administrators/Developers Use all objects
End users with read/write permission Use forms to display, add or modify data entries
they are allowed to access End users with read-only permission
Read data from reports End users have no knowledge of macros
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Tables
Tables contain columns and rows, or Fields – store different types of data, and Records – collect all the information of a particular
instance of the subject (or an entity) No two records may be identical A set of attributes which can uniquely identify a record is
referred to as a primary key of the entity. For two different records, their primary keys may have the
same value.
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Design & Normal Views
Design view is used during development Normal view is used
By end users during operation By developers during development, to make sure
their product looks right For tables, normal view is the datasheet view,
in which data are represented in a tabular format
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Data Validation
Data validation is a crucial part of any database system Some simple validations are supported
automatically by Access A non-numeric value is entered to a field which is integer
by definition More sophisticated validation are implemented by
user Garbage In, Garbage Out (GIGO) – no system can
produce valid output from invalid input
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Forms
Forms are used to Control and enhance the way the data looks Perform extensive editing using macros Link multiple forms or reports by using macros that
are run from buttons on a form Forms can be displayed in
Design view, or Form view
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Queries
Queries can be used to select data from one or more tables E.g., to select club names and addresses from the
club table The outcome of a query can also be
represented by a table Queries can be displayed in two views
Design view Datasheet view
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Filters & Sorting
Filter by selection Filter by form
Specify multiple criteria simultaneously Specify logical relationship among criteria
Logical AND or logical OR
Remove filters Sorting in
Ascending order, or Descending order
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Example – Filter By Form
Filterdefinition
Original data
Filtered data
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Reports
Reports help to format your data in an attractive fashion & be ready for printing
They can also help to carry out Calculating Grouping and summarizing
Features frequently used include Page header and footer Grouping and summarization
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Data Access Pages
Data access pages can publish your data as Web pages To display them, Access is needed on the user’s
local machine Used by employees on the company’s intranet, to
view and/or modify data The two views are
Design view Page view
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Macros
A macro cannot be displayed, it can only be run No normal view, only design view available
A macro doesn’t relate to data directly, but to actions on data Take effects only through forms and reports on
which a macro is embedded
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Objects & Their Relationships
Tables
Queries
DA Pages
Forms Reports
Macros
Trigger Trigger
Open/Filter Print/View/Filter
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Modules
Similar to macros, cannot be displayed, only triggered from other objects Include a number of VBA procedures or functions to
provide more power in more flexible ways