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02 – Queries: Query by Example

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Questions: Databases

• Consider the following table:

a) How many records does it contain?

b) How many fields does it contain?

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Session Aims & Objectives• Aims

– Introduce you to queries

• Objectives,by end of this week’s sessions, you should be able to:

– create a query using 'query by example' to:• extract a subset of records and fields from a database

table

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Creating Queries: New Query• Select the database window

• Select queries option

• Double click on Create Query in Design view

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Creating Queries: Add Table

• Click Add button

• Click Close button

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Creating Queries: Add Fields

• Drag field names into query

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View you Query

• Click View button

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Return to Query Design

• Click View button again

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Modify your Query

• Type in criteria

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Criteria

• Massive variety – very powerful:> greater than

< less than

= equal to

>= greater than or equal to

<= less than or equal to

<> not equal to

Like "*or*" * means any text (i.e. contains "or")

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Tutorial Exercise 1: Plants database• LEARNING OBJECTIVE:

to understand table, field, and record, so that you can create your own database with a single table containing several fields and records using MS Access

• TASK: Create the plants database (shown in earlier slide).

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Tutorial Exercise 2: Plants database• LEARNING OBJECTIVE:

to understand queries, so that you can create your own query that displays selected fields and records from a table using MS Access

• TASK 1: Create the query (shown in earlier slide).• TASK 2: Experiment with Show, Sort and Criteria combinations