ParameterExpression

The ParameterExpression is part of the Dynamic Where feature; it represents a parameter in where expressions.

№ Implementation

Example

Target SQL where clause:

WHERE LASTNAME LIKE :p

 

WhereExpression where = new BinaryExpression(
                          new FieldExpression("SALESMEN","lastname"),
                          new ParameterExpression("p", DataType.String, 120),
                          BinaryOperator.Equal);

 

let whereExpression = BinaryExpression(
            FieldExpression("SALESMEN", "lastname"),
            ParameterExpression("p", DataType.String, 120),
            BinaryOperator.Equal)

 

WhereExpression where = new BinaryExpression(
                          new FieldExpression("SALESMEN","lastname"),
                          new ParameterExpression("p", DataType.String, 120),
                          BinaryOperator.Equal);

 

let whereExpression = BinaryExpression(
            FieldExpression("SALESMEN", "lastname"),
            ParameterExpression("p", DataType.String, 120),
            BinaryOperator.Equal)

 

with ClientDataModule.tbl_SALESMEN,DynamicWhere do begin
  Expression:=NewBinaryExpression(
                NewField(LogicalName,'lastname'),
                NewParameter('p', datString),
                dboLike);
end;

 

myTable.dynamicWhere = new RemObjects.DataAbstract.DynamicWhere(
        new RemObjects.DataAbstract.BinaryExpression(
          new RemObjects.DataAbstract.FieldExpression("LastName"),
          new RemObjects.DataAbstract.ParameterExpression("p", "String", 120), "Equal")
        ));

Generated XML/JSON

<?xml version="1.0"?>
<query xmlns="http://www.remobjects.com/schemas/dataabstract/queries/5.0" version="5.0">
  <where>
    <binaryoperation operator="Like">
      <field tablename="SALESMEN">lastname</field>
      <parameter type="String">p</parameter>
    </binaryoperation>
  </where>
</query>

{
  "type": "query.where",
  "expression": {
    "type": "binaryoperation",
    "left": {
      "type": "field",
      "field": "lastname",
      "table": "SALESMEN"
    },
    "operator": "Like",
    "right": {
      "type": "parameter",
      "name": "p",
      "datatype": "String"
    }
  }
}