Download Tables

Microsoft Access
(Tables)
[email protected]
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Introduction
 What’s Access?
 Access is a relational database application
designed to handle thousand or a few records
depending upon the user needs
 Access can simply list a collection of names and
addresses in a single table, or manage complex
relationships between data that pan several
tables
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Introduction
 Database tables are collections or lists of
records, each record holding individual
pieces of information in fields
 As a database Management System
(DBMS), Access enables a user to create
and maintain these tables, employing
sophisticated, yet easy-to-use, tools to
facilitate defining, constructing, and
manipulating data
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Introduction
 To plan a database you need to do the
following:
 Decide what the function of the database will be
 Determine what information you need, where this
information will come from and how it will be
entered into the database
 Determine the structure of the database and the
relationships between the various tables
 Decide on the structure of the tables including
field names, field types and input validation.
 Decide which forms, reports and queries you will
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use
Getting Started …
 In Access, a database application is
composed of database objects, which are:
 Tables
 Forms
 Queries
 Reports
 Pages
 Macros
 Modules
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Getting Started …
 Access centralizes all database application into a single
database file. All the tables, forms, reports, and other
Access objects, designed for the database, are stored in
this file
 Having a single database file not only eliminates
keeping tracks of a large number of individual files,
but also permits an Access database to be transported
much easier than other database types
 Before you can begin constructing the individual
database object types, you must first create an Access
database file to contain the objects
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Tables
 Design a table:
 You can add individual fields to a blank table structure
using the panes in Table Design View
 The top pane is the grid and is used to specify a field’s
name, descriptive text, and data type.
 The bottom pane is the field properties section and is used to
specify field size and other attributes
 Each row in the grid corresponds to one field; a collection
of all fields is grouped into a record
 Access denotes that one field in every table contains unique
entries that distinguish that record from others, this is the
primary key field. The primary key field is denoted by a key
symbol in the field’s row selector box to the left of the 7field
row
Tables
 Design a table:
 Within each field, there are three corresponding
columns in the grid:
 The first is the field name column, which defines the name of
the field
 The second is the data type column, which regulates what type
of data a field can hold, such as numbers, text, and dates
 The third column is the description; information in the
description column appears in the status bar when the field is
selected in either a form or datasheet view
 Field names appear as column headers in Table
Datasheet View
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Tables
 Design a table:
 A fundamental part of designing an Access database
table is knowing the proper data type to assign to a
field.
 A correctly defined field not only lends itself to
greater efficiency, but can also reduce compatibility
problems when your database application places
more demands on the data, such that in calculations
or concatenation
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Tables
 Design a table:
 Access data types are:
 AutoNumber holds records numbering (either incremental
or random)
 Date/Time
holds dates & times (in a variety of common
formats)
 Currency
holds currency values
 Text
holds characters, numbers, punctuation
marks, and special symbols
 Memo
stores a large quantity of text information
 Number
holds only numbers, + or – signs, and
decimal places
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Tables
 Design a table:
 Access data types (cont.):
 Yes/No
stores either a Yes or No value; appears in
datasheet view as a checkbox (also called a
logical or Boolean type)
 OLE
holds graphics, sounds, and other object
Linking & Embedding objects
 Hyperlink
stores URLs for Internet locations
 Lookup
Wizard
creates a field that allows you to retrieve
value from another table
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Tables
 Enter & delete data:
 Creating a database table is a two-part process; the first part
defines the structure of the table. The second part of the
process involves input from the user; this usually demands
physically typing the data into the table
 Data can be entered directly into a database table using the
table’s datasheet view; this view displays a table in a grid
format. Each row in the grid is a record, with each cell being
an individual field. You enter data by typing values directly
into these cells
 When you advance to a previous or new blank row, Access
writes the data to the table
 A single new blank record row will appear at the bottom of the
grid and is denoted by an asterisk (*) in the row selector
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Tables
 Format the datasheet:
 You can format the datasheet view to make data entry and viewing
easier and more productive
 You can adjust each field (or column width) in the grid to better
view its data. The data may not fully display because the default
column width is too narrow. You can click and drag a grid line to
manually resize a column or modify the column’s properties
 Access also enables you to change the text attributes (font size &
style, and color of text) of data appearing in the grid. The
modification of these characteristics is applied to all text in the grid
 Changing the column order of fields in the datasheet view will not
modify field order in the actual table structure
 Renaming a column header will rename the actual field name
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Tables
 Filter & sort tables:
 Records display in the order in which they were created by default
 Access provides sorting and filtering features to assist you in
organizing and delineating table data as the number of records
increases
 Records can be sorted in either ascending (low to high) or
descending (high to low) order based on a selected field
 Filtering data involves specifying conditions that a record must
meet to be selected. Filters can contain single or multiple conditions
(tests) that must be met for a record to be listed. A set of records
produced as a result of a filter is known as a dynaset
 You can apply two or more filters to the same table; in such case
logical conditions such as AND or OR are used
 When a table is closed, sorted or filtered records return to their
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original state
Tables
 Edit field attributes:
 You can make permanent modifications to the
structure of a new or an existing table using design
view. A new table may need modification after initial
data entry has exposed problems. Existing tables may
have to adapt to new data or be modified to function
under different circumstances
 Access enables you to change the data type of fields that
already contain values. However, certain changes don’t
provide for successful data conversions, such as
attempting to convert a field full of characters (text) to
a number value
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Tables
 Change format properties:
 Access by default displays data in the same format as
it was entered. You can have data displayed in a
different format.
 Access allows you to alter the display format but not
the value of data
 Located in the field properties pane of table design
view, the format property can access and implement
predefined formats (dependent on data type), or allow
you to construct a custom layout of your own
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