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Creating Formulas in a Catalog

Predefining formulas in a catalog

Creating formulas in a catalog when needed

Referencing parameters in formulas

Referencing special fields in formulas

Using DBArray in formulas

Formula examples

This section introduces creating formulas in a catalog. In a report that uses business view as the data source, you can also create dynamic formulas to use in the report specifically.

See also Formula Fields for how to work with formulas as component in a report.

Predefining formulas in a catalog

You can predefine formulas in a catalog so as to use them directly in reports.

1. Open the required catalog.
2. In the Catalog Manager, expand the data source in which to create the formula, then:
   • Select the Formulas node or any existing formula in the data source and click New Formula on the Catalog Manager toolbar.
   • Right-click the Formulas node in the data source and click New Formulas on the shortcut menu.
3. In the Enter Formula Name dialog, provide a name for the formula and click OK. The Formula Editor appears.

   

4. Compose the formula by selecting the required fields, including DBFields, other formulas, summaries and parameters in the current catalog data source and some special fields from the Fields panel, and functions and operators from the Functions and Operators panels. When the predefined formulas, summaries and parameters cannot meet you requirement, you can create new formula, summary and parameter to be referenced by the formula using the New XXX option on the toolbar. The newly created objects are saved into the same catalog data source as the formula. You can also write the formula by yourself in the editing panel. You should have some knowledge of the formula syntax before you can successfully compose a formula with no errors.
5. Make use of the buttons on the toolbar above the editing panel to edit the formula. To comment a line, click the Comment/Uncomment button on the toolbar. If you want to bookmark a line so that it can be searched easily later, click the Add Bookmark button . To check whether or not the syntax of your formula is correct, click the Check button .
6. Click OK to add the formula.

Creating formulas in a catalog when needed

Besides predefining formulas in a catalog via the Catalog Manager, JReport Designer also provides you quick access to create formulas in a catalog from the UI where a formula list is available, for example in the Resources box of the report wizard. In this formula list, the <New Formula...> item is provided on the top. By clicking the item, you can create any formulas you want with the Formula Editor, which are then added into the current catalog.

Referencing parameters in formulas

A formula which references parameters will return values according to the parameter values. To reference a parameter in a formula, follow the syntax: @ParameterName.

Assume there is a type-in parameter pCompany of String type, you can reference it in a formula to display the URL for a company dynamically.

1. Create a formula named CompanyURL in the Formula Editor as follows:

   "http://www." + @pCompany + ".com"

   Here, you can either manually type @pCompany, or you can select it from the Parameters node in the Fields panel (if you choose this way, the @ sign will be automatically inserted).

2. Insert the formula into a report.
3. View the report result, and type the string Jinfonet when prompted to enter the parameter value for pCompany. You will then find that the value of the formula becomes http://www.jinfonet.com.

There may be times you need to display the value of a multi-valued parameter. The built-in function join() assists with that. For example, the following expression will show a list of selected states separated by commas:

"Selected States : " +  trim(join (@pStates,",")) + "\r\n"

Referencing special fields in formulas

You can also reference some special fields in formulas in the format fieldname. These special fields include: User Name, Print Date, Print Time, Fetch Date, Fetch Time, Modified Date, Modified Time, Record Number, Page Number, Global Page Number, Total Records and Total Fetched Records. They can all be divided into two types (page level and constant level) according to the time when their values are ready.

Page level

The value of this special field is ready at the time when the report result is generated. A formula which references a page-level special field is treated as a page-level formula. In which, the formula is calculated more than once.

The special fields of this type are: Fetch Date, Fetch Time, Print Date, Print Time, Record Number, Page Number, Global Page Number, Total Records and Total Fetched Records.

Constant level

The value of this special field is ready at any time before the engine runs. A formula which references a constant-level special field is treated as a constant-level formula, and is calculated only once.

The special fields of this type are: User Name, Modified Date and Modified Time.

Using DBArray in formulas

JReport Designer supports a multiple-value field, which contains a set of values in a single field, in a formula. Using the multiple value field is the same as using an array in a formula. You can refer to a field with multiple values as with a normal field in a formula, such as @FIELDNAME, and then use the array functions that JReport Designer provides in the Formula Editor to manipulate the values in it. JReport Designer first converts this field into a normal array, and then manipulates it in the usual way.

For example, normally an array in a formula is manually defined as follows:

Integer myArray[4]=[1, 2, 3, 4]; //Datatype ArrayName[ArraySize]=[ArrayContent];

The array may be referred to in this way:

integer myInt=3;
myInt in myArray;

If a field, named myField for example, contains a similar array value, it can be referred to similarly:

integer myInt=3;
myInt in @myField;

If you want to display all the values of an array, you can use the join() function to return a string of all the values.

Formula examples

Example 1: TerritoryUSA

if (@State in ["CT", "ME", "MA", "NH", "NY", "RI", "VT"]) {
  "NorthEast, USA";}
else if ( @State in ["DC", "DE", "MD", "NJ", "PA", "VA"]) {
  "MidAtlantic, USA";}
else if ( @State in ["CO", "ID", "KS", "MT", "NE", "NV", "NM", "ND", "SD", "UT"]) {
  "Rockies, USA";}
else if ( @State in ["AZ", "AR", "LA", "MO", "OK", "TX"]) {
  "South, USA";}
else if ( @State in ["AL", "FL", "GA", "MS", "NC", "SC"]) {
  "SouthEast, USA";}
else if ( @State in ["AK", "CA", "HI", "OR", "WA"]) {
  "West, USA";}
else if ( @State in ["IL", "IN", "LA", "KY", "MI", "MN", "OH", "TN", "WI", "WV", "WY"]) {
  "MidWest, USA";}

• Purpose: In your sales report, you want JReport to print out which territory the customer belongs to according to the abbreviated state names stored in the State field.
• Explanation: In the six else-if statements, JReport will retrieve the value of the State field, and compare it with the values in brackets []. If a value matches the value in brackets, the formula will return the territory name.

Example 2: DateToMonth

Number m = Month ( @"Order Date" ) ;
String str = "";
if ( m == 1 ) {
  str = " January Sales";}
else if ( m == 2 ) {
  str = " February Sales";}
else if ( m == 3 ) {
  str = " March Sales";}
else if( m == 4 ) {
  str = " April Sales";}
else if( m == 5 ) {
  str = " May Sales";}
else if ( m == 6 ) {
  str = " June Sales";}
else if ( m == 7 ) {
  str = " July Sales";}
else if( m == 8 ) {
  str = " August Sales";}
else if ( m == 9 ) {
  str = " September Sales";}
else if( m == 10 ) {
  str = " October Sales";}
else if ( m == 11 ) {
  str = " November Sales";}
else if ( m == 12 ) {
  str = " December Sales";}

• Purpose: In your sales report, you want JReport to print out the month name of the orders, so that you can compare the orders of each month in a year.
• Explanation: Since the database field Order Date is of the TimeStamp data type, the built-in function Month (DateTime) is first used to extract the month portion of Order Date. Then, the else-if statement is used to decide the month according to the return value of the function, and assigns a String value which contains a relative month name to the pre-declared string variable str.

Example 3: SectionInvisible

boolean s;
if (pagenumber==1){
  s=true;}
else {
  s=false;}

• Purpose: This formula is used to control the Suppressed property of a certain section such as Page Header, so that the section will be suppressed on the first page of the report.
• Explanation: Since it is only required to suppress the section on the first page, if only the Suppressed property of the section is set to true in the Report Inspector, then it will be suppressed on every page. In this formula, a Boolean type variable is first declared. Then, an else-if statement is used to decide whether or not the page is the first page. If the statement is true, true is assigned to "s". If the statement is false, false is assigned false to "s". In this formula, pagenumber is a special field.

Example 4: Running total of page

You can use the running total function to calculate the sum of one page. And to use the running total function, you have to create a set of formulas.

1. Create a formula named Formula1 as follows to initialize a global variable as the sum variable. And insert it into the Banded Page Header panel. The reference to PageNumber forces the calculation to run after the page break. For more information, see Formula Levels.

   pagenumber; global number pagetotal; pagetotal=0;

2. Create a formula named Formula2 as follows to accumulate the value. And insert it into the Detail panel.

   pagetotal=pagetotal+@"YTD Sales";

3. Create a formula named Formula3 as follows to display the sum of one page. And insert it into the Banded Page Footer panel.

   return pagetotal;

Example 5: Running total of group

This example will accumulate the total of the successful and failed shipments for each group.

1. Create a formula named Formula1 as follows to initialize the value. And insert it into the group header.

   global integer iFail; global integer iSuccess; iFail=0; iSuccess=0;

2. Create a formula named Formula2 as follows to accumulate the value of the successful and failed shipments, and insert it into the Detail panel.

   if(@Shipped) { iSuccess=iSuccess+1; iFail=iFail; } else { iSuccess=iSuccess; iFail=iFail+1; }

3. Create a formula named Formula3 as follows to return the successful shipments and the failed shipments, and insert it into the group footer.

   return "Total successful shipments is "+ iSuccess +" and total failed shipments is "+ iFail;

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