DAY 19: MICROSOFT ACCESS – CHAPTER 3 CONTD. Aliya Farheen [email protected] March 17, 2015.

DAY 19:MICROSOFT ACCESS – CHAPTER 3 CONTD.

Aliya Farheen

[email protected]

March 17, 2015

ANNOUNCEMENT

• Homework #4 –Access is Released.• Due Date is 4/3/2015, Friday by 11:59 pm.

CONTENTS

• Basic Queries- Exact match condition- Adding Criteria- Using AND/OR - Sorting- Wildcards- Operators- Calculated field using the Expression builder

EXERCISE

• Go to the lecture notes page and Download Music_extended.accdb.

SPECIFY AN EXACT MATCH CONDITION

• An exact match condition only shows records that match your criteria in the “Criteria” row of the query design grid

• The field values of the records for the field the criteria is specified in must match the condition exactly to be shown in the query results

EXERCISE

• Create a new query in design view• Add 3 tables: Bands, Countries, &

Members…

EXERCISE

• Add the following fields from these tables:• [Bands] BandName• [Member] FirstName, LastName• [Countries] Country

• Run the Query to see the unrestricted results of all the 16 records

ADDING CRITERIA

• Return to Design View• In the criteria row for Country, type

England to have it show us a Dynaset with only band members from England

• Rerun the query• Change England to America and rerun• Try Portugal to see that nothing returns!

USING COMPARISON OPERATORS… “AND” / “OR”

• When using multiple conditions for a query, you can use the logical operators to combine conditions– The “And” logical operator specifies that

both conditions must be met – The “Or” logical operator specifies that

one or the other of the conditions must be met

USING “AND” AND “OR”

• When you enter two conditions in the same row of the query design grid, an “And” condition is created

• If you enter two conditions that are on separate rows, an “Or” condition is created

ILLUSTRATION OF “AND” & “OR” LOGIC

CREATING “AND” CONDITIONIN THE DESIGN GRID…

LET’S TRY AN “AND”

• Clear any existing criteria• Add the field [Members] Living• Type England in the Country row and

create the AND condition by placing Yes in the Living row to return all living band members from England

• Run it• Go back and change Yes to No and

rerun

LET’S DO AN “OR”

• Remove the old criteria• We will set the criteria to show all

members from Rush OR anyone from any band that is living at all from the list of members…

• First lets put “Rush” in the [Bands] Name field and run to see the results

CREATE THE “OR”

• We wish to not only see the members of Rush, but also in addition to them, anyone that might be alive in the members table.

• In Design view, type “Yes” in the OR row for [Members] Living

• You should now see a list of 10 additional records (13 total)

SORTING RESULTS BY DATA TYPE…

SORT EXERCISE

• Open the RockTrivia Query in Design View• In the Sort row for the BandName field,

have it sort the records in Ascending Order• Run the Query

TWO-LEVEL SORT

• Leave the existing sort in place and move the last name field so that it is before the first name field in the Design view…

• Click once to select it… let go and then click and drag to move it over

• Add a secondary sort by having it do Last Name in Ascending order

• Run it. Last names are now show alphabetically inside the band names

WE CAN ALSO USE “WILDCARDS”

WILDCARD EXAMPLE

We want to see all members whose last names begin with “E”…

• Remove all existing sort options• In the last name field, type the letter E in

Criteria and run the query.• (No results show as no one has just the

letter E for a last name)• Make it read E* and rerun to get any other

characters…

WILDCARDS CONTINUED

• Change the criteria to show people whose last names end in “N”• *N

• Run it and we should see 7 records.• Remove all criteria.

USING FIELDS WITHOUT SHOWING

• It is possible to use a field in searching but not show that field in the query results

• Let’s say we want to see all band members whose bands begin and end in “d”, but not see the band name

• Remove the “Show” row checkmark for BandName

• Create the criteria and run !

OPERATORS

Note: This technique is similar to what part of a query asks for in HW4 !

CRITERIA & OPERATORS EXERCISE

• Go to Design view for RockTrivia, add the Born field, and clear criteria, re-show BandName

• In the criteria row for born, add: >1/1/1960 • Note we get 3 records• Try making it: >=1/1/1950 AND <=1/1/1960• We get 9 Records• Change it to: <1/1/1960• We get 13 records

CALCULATIONS IN A QUERY…

• Mathematical calculation can be done as part of the query..

• We often do this for things that we do not need to store and take up space with

• Expressions can be entered into the query design grid as if they were regular fields

• Done on data type fields treated as numbers

CALCULATIONS IN A QUERY…

• To perform a calculation in a query, you must created a calculated field in query design.

• Make certain that you are following the rules of precedence !(Please Excuse My Dear Aunt Sally)

• Two options for entering expressions: – Enter the expression directly into the field text

box– Enter the expression in the Expression Builder

CREATING A CALCULATED FIELD

• Remove the existing criteria • Click in the next available blank field

where the name would be, and then click the magic wand “Builder” icon above

• The expression builder shows up…

THE EXPRESSION BUILDER…

LET’S MAKE A QUERY TO TRY THIS…

• We want to figure out how many years they are alive. It would be inefficient to store this as we would have to update it all the time.

• Build or type the following:– Age: (Date()-[Members]![Born])/365

Note: If you see <<expr>> be sure to remove it ! ! !

• Run it !• Expand the width of the column if you see ####

CHANGING DECIMALS PRECISION

• Note: Similar to what is needed for to set decimal places on query results in homeworks!!

YOU MUST RUN THE QUERY ONCE FIRST !• In design view, right click Age field• Click Properties• Select Fixed for Format and 0 for Decimal

Places• Re-run it to see it without the decimal places

Questions ?