Using query()

As the name implies QueryRun is the executor of a query linked to it. To construct a query you want QueryRun to execute, you need build classes:

 

Query

 QueryBuildDataSource

QueryBuildRange

QueryBuildFieldList

QueryBuildLink

QueryBuildDynaLink

Today’s example will use the first four to demonstrate a query that sums the credit limit field in CustTable grouped by Country and Currency. Additionally a count field indicates how many records are represented in the sum. Ranges are implemented for AccountNum and Country, but the user is allowed to add additional range criteria in the dialog. To demonstrate the status() property I have locked it, so the user can not change it.  

QueryRun 

QueryRun executes the query. If needed the familiar query dialog can be opened before the query is run. This is done using the prompt() method. SysQueryRun extends QueryRun and has a total of 7 prompt*() methods, with different default behavior. For example promptAllowAddRange() would allow the user to add new where-conditions. 

Query 

A query represents the select statement. This is where all the strings come together. 

QueryBuildDataSource 

Using QueryBuildDataSources you add all the tables you want joined (just one in this example). This is also where you define how the resultset is to be sorted. The orderMode() method lets you define 

OrderBy

GroupBy 

QueryBuildRange 

Ranges represent where conditions. Multiple ranges are connected with AND conditions. Unfortunately there is no easy way to change that. 

QueryBuildFieldList 

Represents the selected fields of the query. By default all fields are selected. In regular queries you probably wouldn’t use them that often, but when grouping this is the way to define which fields are calculated. SelectionField is an enum with the following values 

 Avg

Count

Database

Max

Min

Sum   

The result of Test_Query on my test system looks something like this: 

CA CAD     1120,00 (3 records) 

CA USD      500,00 (1 records) 

DE EUR        0,00 (1 records) 

DK CAD     5000,00 (1 records) 

DK EUR      300,00 (6 records) 

DK GBP      560,00 (2 records) 

ES EUR        0,00 (1 records) 

IE EUR        0,00 (1 records) 

NL EUR       20,00 (2 records) 

NO EUR     3000,00 (1 records) 

static void Test_Query(Args _args) 

{ 

    CustTable            custTable; 

    Query                query      = new Query(); 

    QueryRun             qr         = new queryRun(query); 

    QueryBuildDataSource qbds       = qr.query().addDataSource(tableNum(CustTable)); 

    QueryBuildRange      qbrAccN    = qbds.addRange(fieldNum(CustTable,AccountNum)); 

    QueryBuildRange      qbrCountry = qbds.addRange(fieldNum(CustTable,Country)); 

    QueryBuildFieldList  qbfl       = qbds.fields(); 

    ; 

    qbrAccN.value('4000..4050'); 

    qbrAccN.status(RangeStatus::Locked); 

    qbrCountry.value('CA..NO'); 

    qbfl.addField(fieldNum(CustTable,CreditMax),SelectionField::Sum); 

    qbfl.addField(fieldnum(CustTable,RecId),SelectionField::Count); 

    qbds.addSortField(fieldnum(CustTable,Country)); 

    qbds.addSortField(fieldNum(CustTable,Currency)); 

    qbds.orderMode(OrderMode::GroupBy); 

    if (qr.prompt()) 

    { 

        while (qr.next()) 

        { 

            custTable = qr.get(tableNum(CustTable)); 

            print strfmt("%1 %2 %3 (%4 records)",custTable.Country,custTable.Currency, 

                         num2str(custTable.CreditMax,10,2,0,0),custTable.RecId); 

        } 

    } 

    pause; 

}