26.3 Create a Multiple-Query Matrix

You can build a matrix report with multiple queries in the data model. A multiple-query data model is typically easier to conceptualize and code than a single-query, but the single-query data model typically performs better.

26.3.1 Create a new report manually

In this case, it is easier to create the data model and layout separately. Hence, we will create an empty report first, then add the queries, and then create the layouts.

To create a blank report:

  1. Choose File > New > Report.

  2. Select Build a new report manually, then click OK.

26.3.2 Create a data model with a cross product and data links

When you create a matrix report with multiple queries, it is typically easier to create all of the queries with the Data Wizard first and then create the cross product group and the necessary links in the Data Model view.

To create the queries:

  1. In the Data Model view, choose Insert > Query to display the Data Wizard.

  2. If the Welcome page displays, click Next.

  3. On the Query page, type Q_Year for the Query name, then click Next.

  4. On the Data Source page, select SQL Query, then click Next.

  5. On the Data page, enter the following SELECT statement in the Data Source definition field:

    SELECT DISTINCT TO_CHAR (HIREDATE, 'YY') YEAR
    FROM EMP
    
    

    Note:

    You can enter this query in any of the following ways:

    • Copy and paste the code from the provided text file called nested3_code.txt into the Data Source definition field.

    • Click Query Builder to build the query without entering any code manually.

    • Type the code in the Data Source definition field.

  6. Click Next.

    Note:

    If you are not already connected to a database, you will be prompted to connect to the database when you click Query Builder or Next. Ensure that you connect to a database that has the appropriate schema for this example. Section 26.1, "Prerequisites for This Example" describes the sample schema requirements for this example.

  7. On the Groups page, click Next.

  8. Click Finish to display the data model for your report in the Data Model view.

  9. Repeat the steps above for a second query, but this time name your query Q_Dept and use the following SELECT statement:

    SELECT DISTINCT DEPTNO
    FROM EMP
    
    

    Note:

    You can enter these queries in any of the following ways:

    • Copy and paste the code from the provided text file called nested3_code.txt into the Data Source definition field.

    • Click Query Builder to build the query without entering any code manually.

    • Type the code in the Data Source definition field.

  10. Again, repeat the steps above for a third query, but this time name your query Q_Job and use the following SELECT statement:

    SELECT DISTINCT JOB
    FROM EMP
    
  11. Again, repeat the steps above for a fourth query, but this time name your query Q_Salary and use the following SELECT statement:

    SELECT TO_CHAR(HIREDATE, 'YY') YEAR,  DEPTNO,  JOB,
    SUM(SAL) FROM EMP
    GROUP BY TO_CHAR(HIREDATE, 'YY'),  DEPTNO,  JOB
    ORDER BY TO_CHAR(HIREDATE, 'YY'),  DEPTNO,  JOB
    
    

    Figure 26-5 Data model with four queries

    Description of Figure 26-5 follows
    Description of "Figure 26-5 Data model with four queries"

    Tip:

    The order of the queries is significant in this case. Q_Dept must appear to the right of or below Q_Year in order for the values of DEPTNO to be nested inside of the values of YEAR in the output.

To create the cross product group:

  1. In the Data Model view, click the Cross Product tool in the tool palette.

  2. Drag a box around G_YEAR, G_DEPTNO, and G_JOB. When you release the mouse button, the cross product group is created. Ensure that it completely surrounds all three groups.

Figure 26-6 Data Model with four queries and a cross product group

Description of Figure 26-6 follows
Description of "Figure 26-6 Data Model with four queries and a cross product group"

To add the data links:

  1. In the Data Model view, click the Data Link tool in the tool palette.

  2. Click and drag from the YEAR column in the G_YEAR group to the YEAR1 column in the G_YEAR1 group.

  3. Repeat steps 1 and 2, but this time drag the link between the DEPTNO column in G_DEPTNO and DEPTNO1 in G_YEAR1.

  4. Again, repeat steps 1 and 2, but this time drag the link between the JOB column in G_JOB and JOB1 in G_YEAR1.

    Figure 26-7 Nested matrix data model

    Description of Figure 26-7 follows
    Description of "Figure 26-7 Nested matrix data model"

  5. Optionally, move the data model objects around to appear like the above figure.

26.3.3 Create the layout with the Report Wizard

Once your data model is complete, you need to create a layout for the data objects to display in the report output.

To create the layout:

  1. In the Data Model view, right-click on the canvas, then choose Report Wizard.

  2. In the Report Wizard, on the Report Type page, select Create Paper Layout only.

  3. On the Style page, select Matrix.

  4. On the Groups page, ensure that all of the groups from your data model appear in the Displayed Groups list. G_1 should be Matrix, G_YEAR and G_DEPTNO should be Down, G_JOB should be Across, and G_YEAR1 should be Down.

    Figure 26-8 Groups page of the Report Wizard

    Description of Figure 26-8 follows
    Description of "Figure 26-8 Groups page of the Report Wizard"

  5. On the Fields page, ensure that only the following columns appear in the Displayed Fields list:

    • YEAR

    • DEPTNO

    • JOB

    • SUM_SAL

    Figure 26-9 Fields page of the Report Wizard

    Description of Figure 26-9 follows
    Description of "Figure 26-9 Fields page of the Report Wizard"

  6. On the Labels page, change the labels and field widths as follows:

    Fields Labels Width

    SUM_SAL

    <none>

    10

    YEAR

    <none>

    4

    JOB

    <none>

    10


  7. On the Template page, make sure Beige is selected under Predefined Template, then click Finish to display your report output in the Paper Design view. It should look like this:

    Figure 26-10 Paper Design view for the nested matrix output

    Description of Figure 26-10 follows
    Description of "Figure 26-10 Paper Design view for the nested matrix output"