Today’s Goals Answer questions about homework and lecture 2 Understand what a query is Understand how to create simple queries using Microsoft Access 2007

Today’s Goals• Answer questions about homework and lecture 2• Understand what a query is• Understand how to create simple queries using

Microsoft Access 2007

1R. Kornak, AIT Training, July 2009

Review

Topic 1


IFRI Data Workflow1. Record Field

Data on Paper Forms

3. Manage Data, Create Queries, and Perform Simple Analysis Using Microsoft Access

2. Enter Data Using IFRI Data Entry Application

4. Export Data for Advanced Analysis and Visualization Using Other Software (e.g. Excel, SPSS, STATA, GIS)


Review

• The IFRI database has 24 tables that are linked together based on their relationships

• Most forms correspond with one table

• One row for each instance of a form

• Column names used in the database are found in the IFRI manual in <> after each question

• Each column can only have one data type4

R. Kornak, AIT Training, July 2009

Review

• Coded values are used to represent multiple choice answers

• The codes used in the database are shown in ( ) with each question in the IFRI Manual

• You can use Microsoft Access to explore your data using the sort and filter tools


Introduction to Database Queries

Topic 2


What is a Database Query?

• A way to create subsets of the full IFRI database that address a particular research question

• The result of a query is a table showing only the data you are interested in at a given time

• Allows you to combine data from multiple forms and sites


Database Queries

• Your results can be explored in Access or exported to another program such as SPSS, Excel, or GIS

• Queries can be saved and/or modified for future use– Provides a record of your calculations if you

need to redo them or document them for a paper


Queries Tools in Access 2007

• We will use the “Design View tool” to create queries in this class

• This tool allows us to add tables to a workspace and specify fields from each one that we are interested in

• Similar to a table, you can view your query in design view or data sheet view


Software Demonstration• Description of tools on the create tab

of the ribbon

• Adding a table to a query

• Explore your query in design view and data sheet view

• The “run” button runs your query


Queries in Access 2007

• There are tools to specify how the results should be sorted and filtered using one or more variables

• Similar to the “filter” tool we talked about yesterday except you can use multiple variables at the same time


Software Demonstration


Types of Queries

• There are many different types of queries in Microsoft Access

• Today we are only going to talk about 3 types– Select Queries– Make Table Queries– Summary Queries


Select Queries

• Allow you to select only the variables you are interested in

• A select query does NOT make a copy of your data tables


Select Queries

• The data shown in your results will automatically update if you make changes to your master data tables

• Data in your master tables will automatically update if you make changes in your results table



• Let’s practice by creating a very simple select query using only the OVERSITE table

• Make a change in either your master table or results table and see how they both update

• Save the query for later use


Make Table Queries

• Allow you to select only the variables you are interested in and create a new table from them

• A make table query makes a copy of your data and adds it to a new table


Make Table Queries

• The data shown in your results will NOT automatically update if you make changes to your master data tables

• Data in your master tables will NOT automatically update if you make changes in your results table



• Let’s practice by opening the select query we just made and changing it to a make table query

• Specify a name for your new table and run the query

• Make a change in either your master table or results table and see how they both DO NOT update

• Save the query for later use19R. Kornak, AIT Training, July

2009

Summary Queries• Allow you to create summary statistics

about one or more tables

• Count– e.g. find number of plots per forest or plots

per site

• Average, Total (Sum), Minimum, Maximum, Standard Deviation, Variance– e.g. find the average tree height per plot

• Summary queries can be saved as either make table or select queries 20


Summary Queries• Summary queries are very helpful when you

first begin exploring your data• Similar to the filter tool except you can count

how many of each value occur in your data (histogram)

• You can easily create histograms for each variable to see if there are any significant patterns

• You can easily identify and correct missing or incorrect data

21R. Kornak, AIT Training, July

2009


• Let’s practice by opening the make table query we just finished

• We will make a few small changes to it to create a summary query


Homework 1

• Create a select by query with only the following variables– FNAME– FSIZE– FTOPOGRAPH– FSTEEP

• Save the query as “Select_Forest”


Homework 2

• Using the query “Select_Forest” answer the following questions:

• Which of the variables are coded values and which are measured values?

• How big is the Khog Bung Preu Forest?

• How many forests are “primarily steep”?

• What does the value “0” mean in the FSTEEP column?


Homework 3

• Create a make table query with only the following variables– FK_FOREST– PPIN– PSTEEP

• Save the query as “MakeTable_Plot”

• Run the query and save the table as “Plot_results”


Homework 4

• Using the table “Plot_results” answer the following questions:– What are the units of PSTEEP?– How many plots are in the table?– How many plots are missing data (value of 0) in

the PSTEEP field?– What is the maximum steepness? (hint – use the

sort tool)– How many plots have a value of 5 for

“FK_FOREST? (hint – use the filter tool)26


Homework 5

• Create a new table using a make table query with the following fields:– SNAME– SMARKET– SINDPOP

• Run the query and save the table as “Settlement_Sample”


Homework 6

• What do each of the fields mean in the “Settlement_Sample” table?

• What data type is each field?

• What are the units of SMARKET?


Homework 7• Add the “Settlement_sample” table to a new

query• Select the totals icon and make your query

match the one below

29R. Kornak, AIT Training, July

2009

Homework 8

• Run the query (you may need to rename the table or change it to a select query)

• What is the average distance to market?

• What does the “count” statistic mean?


Homework 9

• Add the PRODUCT table to a new query

• Select the totals icon

• Add the “RNAME” field to your query 2 times

• Under the “Total Option” choose “Group By” for the first RNAME and “Count” for the second RNAME



Homework 10

• You just created a histogram of product types

• How many unique products are in the table?

• What are the 3 most common products?


Documents

Today’s Goals Answer questions about homework and lecture 2 Understand what a query is Understand how to create simple queries using Microsoft Access 2007