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Database. Lesson 02 – Database Development. Overview. Data Dictionary. Tables and Forms. Data Dictionary. Data dictionary is description of each field in a database. Field name – is name of the field Data type – is the kind of data in the field. - PowerPoint PPT Presentation
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Q.Nand 1
Database
Lesson 02 – Database Development
Q.Nand 2
Overview
• Data Dictionary.
• Tables and Forms.
Q.Nand 3
Data Dictionary
• Data dictionary is description of each field in a database.– Field name – is name of the field– Data type – is the kind of data in the field.– Field size - is the number of characters
allowed in each field.– Description - specifies the contents of the
field.
Q.Nand 4
Field Name
• Relatively short
• Clear
Q.Nand 5
Data Type
• Text– Used for text or numbers
that do not require calculations, such as phone number.
• Eg: – (02) 9735 7563– Adams David
• Memo– Used for lengthy text and
numbers.• Eg:
– Description
• Number– Used for numeric data to be
included in mathematical calculations.
• Eg: 1235
Q.Nand 6
Data type (Cont…)
• Currency– Used for currency
values• Eg: $
• AutoNumber– Used to automatically
create a unique number when a record is added.
• Yes/No– Used for data that can
be only one of two possible values.
• Eg: Checked list.
Q.Nand 7
Data type (Cont…)
• Date/Time– Used for dates and times.
• OLE object– Used for data created in
other programs such as spreadsheet graphic or sound.
• Hyperlink– Used for hyperlinks to link
from 1 slide to another or to different file.
Q.Nand 8
Field Size
Number of characters allowed in each field.
eg:Phone number =
02 9465 8364
Q.Nand 9
Description
specifies the contents of the field.
Q.Nand 10
Tables
• A table or a list displays data using:– Columns as Field and– Rows as Records
Column
Row
Q.Nand 11
Form• A form or label usually displays data
for every field of a single record.
• The layout of a form can be changed.
Q.Nand 12
Exercise 02
1. Define ‘data dictionary’2. Explain why the data dictionary is such an important
part of a DBMS.3. Propose why it would be better to store a telephone
number as text rather than as a number data type.4. Explain the difference between a table and a form.5. What data type am I?
a) Numeric data to be included in mathematical calculations.b) Data that can be only one of two possible values.c) Data used for text or numbers that does not require calculations.d) Data created in other programs.
Q.Nand 13
Dictionary
• Field name
• Field size
• Description
• Data type
• Table
• Form
Q.Nand 14
References
• G.K. Powers. “Information and Software Technology”.
• Jacaranda. “IST Information and Software Technology”.
