XP Chapter 3 Succeeding in Business with Microsoft Office Access 2003: A Problem-Solving Approach 1 Analyzing Data For Effective Decision Making

Chapter 3 Succeeding in Business with Microsoft Office Access 2003: A Problem-Solving Approach

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XP

Analyzing Data For Effective Decision Making


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XPChapter Introduction

• Filter data in Microsoft Office Access 2003 database Retrieve and examine only records you need

• Sort data Rearrange records in specified order

• Queries Provide quick answers to business questions


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XPFiltering and Sorting Data

• Filter Restricts data in single table to create temporary

subset of records See only certain records in table based on specified

criteria

• Sorting records Organizing in particular order or sequence Sort records regardless of whether table filtered


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XPFiltering by Selection

• Tools Filter by Selection

• Select particular field in datasheet • Display only data that matches contents of field• Specify only one criterion for filter

Filter by Form


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XPUsing Filter by Selection to Display a Temporary Subset of

Records


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XPFiltering by Form

• Specify two or more criteria

• Filter for comparative data Use comparison operators

• AND criteria Selects records that contain all specified values

• OR criteria Selects records that contain any specified values


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XPSorting Data to Increase Information Content

• Organizes data and increases information value

• Access sorts records based on primary key values Use sorting to change order

• To sort Select sort field

• Sort on multiple fields Move fields in datasheet view so that they are adjacent


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XPSorting Data To Increase Information Content

• Primary sort field Access sorts records by this field first


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XPSorting Types of Data


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XPUsing Queries to Answer Business Questions

• Query Database object Stores criteria for selecting records from one or more

tables Save query

• Use it again More powerful than filter

• Display only some fields in table• Create fields that perform calculations


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XPUsing Queries to Answer Business Questions (continued)

• Capabilities of Access queries: Display selected fields and records from table Sort records on one or multiple fields Perform calculations Generate data for forms reports and other queries Update data in database Find and display data from two or more tables Create new tables Delete records in table based on one or more criteria


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XPUsing Queries to Answer Business Questions (continued)

• Select query Ask question based on one or more tables in database Result displayed in datasheet

• Called recordset


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XPUsing the Simple Query Wizard to Create a Query

• Simple query wizard Presents list of tables and queries in database

• And fields that they contain Select fields from one or more tables Wizard creates and displays results


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XPAdvantages and Limitations of the Simple Query Wizard


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XPIncluding Summary Statistics in a Query for Data Analysis

• Summary query Groups records Calculate sum, average, minimum, or maximum value

in each selected field Count records in table or query

• Click summary options button


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XPCreating a Summary Query with the Simple Query Wizard


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XPCreating a Query in Design View

• Select query window in Design view has two sections Area for field lists at top of window Design grid below it

• Add tables for query to top part of window Appear as field lists

• Query by example (QBE) Typing search value as a criterion


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XPQuery Design View Tools


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XPCreating Queries with Multiple Criteria

• Most queries involve more than one criterion

• Represent AND criteria Entering conditions in same criteria row in query

design grid

• Specify OR criteria Use “or” row of query design grid


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XPSetting Criteria for the Query in Design View


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XPSpecifying Sort Order in Queries

• Query results appear in same order as data from underlying tables Unless specify sort order when designing query

• Sort order determined from left to right

• Multiple columns must be adjacent to sort on more than one field in datasheet view


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XPRunning a Query

• Click Run button on query design toolbar Access displays datasheet of records

• Save query Save only design Not values from tables displayed in results


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XPUsing Wildcards for Inexact Query Matches

• Wildcard character Placeholder Stands for one or more characters

• Memo fields Use same keywords throughout memos Easily retrieve records later Use wildcards when specifying keyword as a query

criterion • To select records that contain characters before and

after keyword


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XPWildcard Characters Used in Queries


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XPUsing Wildcards for Inexact Query Matches (continued)

• Access inserts Word “LIKE” for criteria with wildcards quotation marks

around text• LIKE “*Spanish*”

Pound signs around dates• #12/*/2008#


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XPComparison Operators


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XPComparison Operators (continued)


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XPVerifying and Printing Query Results

• Verify query results before Distributing query to others Using it as basis for decisions

• Use business knowledge Determine whether results adequately answer question

• Print query datasheet


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XPModifying Query Datasheets

• Improve appearance of query or table datasheet

• Resize column widths in any datasheet Double-click line between field names to resize

columns to best fit


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XPFormatting Options for Query and Table Datasheets


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XPLevel 1 Summary

• Use filtering and sorting to change data display

• Develop queries using Simple query wizard Design view

• Use comparison operators and wildcards to make queries more flexible

• Verify query results using business knowledge


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XPLevel 2 Objectives:Creating More Complex Queries

• Design queries that compare data from more than one table

• Refine table relationships by specifying the join type

• Perform calculations in queries

• Customize queries and their results


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XPEvaluating Data Using Special Types of Queries


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XPUsing Queries to Find Duplicate Records

• Duplicates Query Wizard Searches for duplicate values in fields Improve business operations Designed to identify records that contain same

information in particular field


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XPUsing Queries to Find Unmatched Records

• Find Unmatched Query Wizard Compares records in two specified tables or recordsets Finds all records in one table or query that have no

related records in second table or query Requires that two tables being compared have

common field


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XPLimiting the Records in the Query Results

• Limiting results to only a few records often aids analysis

• Top Values query Sorts and then filters records Display specified number of records that contain top or

bottom values Top Values list box on query design toolbar


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XPTop Values Query Design and Results


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XPUsing Parameter Values in Queries

• Parameter values Phrase usually in form of a question or instruction Enclosed in square brackets Serves as prompt to user to enter value Example

• [Enter a job ID]


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XPParameter Query to Allow User Input when the Query Is Run


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XPAnalyzing Data from More than One Table

• Data from more than one table required to answer question Combine records from two or more tables Display only information needed

• Work in design view to specify criteria for selecting records from multiple tables

• Lines between tables link primary key to foreign key field Primary key designated with 1 Foreign key designated with ∞


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XPAnalyzing Data from More than One Table (continued)

• Join tables Linking of tables using primary and foreign keys Established relationship Or

• Each table shares field with same or compatible data type

• One join field primary key

• If tables do not include fields that can be joined Add one or more extra tables or queries Link tables that contain the data


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XPAnalyzing Data from More than One Table (continued)

• Use queries as source of underlying data for another query in place of one or more tables

• Create queries based on more than one object Should not use any table or query that does not have

common field with at least one of the other tables or queries

Otherwise Access displays every combination of records between two tables


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XPRefining Relationships with Appropriate Join Types

• Inner join Displays all records in one table that have

corresponding values in common field in another table Records must match before being displayed in query

results

• Outer join Display all records of one table Regardless of whether corresponding record stored in

related table


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XPInner Join


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XPLeft Outer Join


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XPRight Outer Join


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XPRefining Relationships with Appropriate Join Types

(continued)

• Outer join types Left Right

• Use join properties dialog box To change join type By default tables related using inner joins


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XPUsing Logical Operators to Specify Multiple Conditions

• Logical operators Test values that can only be true or false

• Place conditions in separate fields in same criteria row of design grid All conditions in row must be met to select record

• NOT logical operator Excludes values that don’t meet criterion


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XPLogical Operators


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XPPerforming Calculations with Queries

• Any information derived from fields in table or query should be calculated in query Rather than included as data in table

• Calculation types Predefined

• Compute amounts for groups of records or for all records combined in query

Custom• Performs numeric date and text computations on each

record • Using data from one or more fields


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XPCalculating Statistical Information

• Aggregate functions Arithmetic and statistical operations Apply to records that meet query’s selection criteria


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XPAggregate Functions


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XPUsing Aggregate Functions in a Query


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XPCreating Calculated Fields in a Query

• Expression Arithmetic formula used to make calculation Use standard arithmetic operators Use parenthesis for complex expressions

• Calculated field Add to query design grid Type expression

• Expression builder Build complex expressions


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XPCreating Calculated Fields in a Query (continued)

• Function Perform standard calculation Return value

• Date() Provides today’s date

• Field properties Change format and number of decimal places for

calculated field


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XPField Properties


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XPConcatenating in Queries

• Concatenation Combining contents of two or more fields Operator

• & Example

• Name [EmpFirst]& " " & [EmpLast]


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XPLevel 2 Summary

• Use queries to select data from more than one table

• Join types Inner Right outer Left outer

• Calculated field types Predefined Custom


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XPLevel 3 Objectives: Exploring Advanced Queries and Queries Written

in Structured Query Language

• Calculate and restructure data to improve analysis

• Examine and create advanced types of queries

• Make decisions in a query using the immediate IF (IIF) function

• Develop queries using SQL


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XPAnalyzing Query Calculations

• Crosstab queries Special type of totals query Performs aggregate function calculations on values of

one database field Determine exactly how summary data appears in

results Calculate and restructure data

• Analyze it more easily Work especially well with time-series data


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XPCreating a Crosstab Query

• To create use Crosstab query wizard

• Often need to create query first Or design view

• Start with select query that includes numeric values or summary calculations


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XPCrosstab Field Settings


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XPModifying Data Using Queries

• Action queries Modify data in table Add records to or delete records from table Create new table

• Backup data before using action query


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XPAccess Action Queries


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XPProcess for Archiving Data


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XPArchiving Data with Make-table Queries

• Make-table query Creates table from some or all of the fields and records

in existing table or query Access does not delete selected fields and records

from existing table


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XPAdding Records to Tables with Append Queries

• Append query Select records from one or more tables by setting

criteria Add those records to end of another table Selected records also remain in original tables Table to which records added must already exist Also use to bring data from another source into

database


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XPRemoving Records from Tables with Delete Queries

• Delete query Removes information from table Based on specified criteria All records meeting criteria permanently removed from

table

• Create select query first Convert to delete query

• Cascading deletes


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XPUpdating Data with an Update Query

• Update query Changes values of data in one or more existing tables Create select query first

• Change type to update query


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XPMaking Decisions in Queries

• IF statement Tests condition Takes one action if condition true Takes another action if condition false

• IIF function Make if decision Format

• IIF(condition to test what to do if true, what to do if false)


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XPCustomizing Queries Using Structured Query Language

• Access designed as database management system (DBMS) for Small businesses Or departments within large businesses

• Structured query language Common query language of most DBMSs Use to query, update, and manage relational databases

• Create query in design view Access translates entries and criteria into SQL

statements


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XPCustomizing Queries Using Structured Query Language

(continued)

• View statements by switching from Design view to SQL view

• SELECT statement defines What data query should retrieve from database How it should present data


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XPExploring the Components of an SQL Query

• Keywords Use to construct SQL statements

• Most developers place each statement on separate line To make SQL code easy to read


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XPCommon SQL Keywords


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XPLevel 3 Summary

• Action queries Make new tables Append data Delete data Update data

• IFF function

• SQL Use SQL view to edit SQL directly


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XPChapter Summary

• Queries retrieve data from one or more tables Action queries update data Perform calculations Make decisions using IFF function

• SQL Used to interact with relational databases Use SQL view to view/edit SQL statements generated

by Access

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XP Chapter 3 Succeeding in Business with Microsoft Office Access 2003: A Problem-Solving Approach 1 Analyzing Data For Effective Decision Making