JSDataSourceNode

Overview

The JSDataSourceNode class facilitates interaction with data source nodes within a Servoy solution model. It enables the creation, retrieval, and management of calculations and foundset methods associated with a data source. * This class is tied to an IApplication instance and a specified data source, allowing dynamic manipulation of related objects.

## Core Functionality

The class provides methods for retrieving and managing calculations and foundset methods. Calculations can be created using JavaScript code, * with the ability to specify types and validate names. Similarly, foundset methods can be dynamically defined and linked to the data source. Both calculations and methods support retrieval, enumeration, and removal, enhancing the flexibility of database scripting.

## Additional Features

The JSDataSourceNode ensures persistence management by integrating with the Servoy framework’s FlattenedSolution and TableNode objects. It supports cloning of script providers and handles runtime exceptions gracefully, ensuring stability. It also provides utility methods like hashCode, equals, and toString for seamless object management in Java environments.

Methods Summarized

Type	Name	Summary
JSCalculation	getCalculation(name)	Get an existing calculation for the datasource node.
Array	getCalculations()	Gets all the calculations for the datasource node.
String	getDataSource()	Get the data source for this node.
JSMethod	getMethod(name)	Get an existing foundset method for the datasource node.
Array	getMethods()	Gets all the foundset methods for the datasource node.
JSCalculation	newCalculation(code)	Creates a new calculation for the given code, the type will be the column where it could be build on (if name is a column name), else it will default to JSVariable.
JSCalculation	newCalculation(code, type)	Creates a new calculation for the given code and the type, if it builds on a column (name is a column name) then type will be ignored.
JSMethod	newMethod(code)	Creates a new foundset method with the specified code.
Boolean	removeCalculation(name)	Removes the calculation specified by name.
Boolean	removeMethod(name)	Removes the foundset method specified by name.

Methods Detailed

getCalculation(name)

Get an existing calculation for the datasource node.

Parameters

• String name The name of the calculation

Returns: JSCalculation a JSCalculation object for the specified calculation name, or null if no such calculation exists.

Sample

var calc = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation() { return 123; }", JSVariable.INTEGER);
var calc2 = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation2() { return '20'; }");
var calc3 = solutionModel.getDataSourceNode("db:/example_data/employees").newCalculation("function myCalculation3() { return 'Hello World!'; }",	JSVariable.TEXT);

var c = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculation("myCalculation");
application.output("Name: " + c.getName() + ", Stored: " + c.isStored());

var allCalcs = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculations();
for (var i = 0; i < allCalcs.length; i++) {
	application.output(allCalcs[i]);
}

getCalculations()

Gets all the calculations for the datasource node.

Returns: Array an array of all JSCalculation objects for the data source node.

Sample

var calc = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation() { return 123; }", JSVariable.INTEGER);
var calc2 = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation2() { return '20'; }");
var calc3 = solutionModel.getDataSourceNode("db:/example_data/employees").newCalculation("function myCalculation3() { return 'Hello World!'; }",	JSVariable.TEXT);

var c = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculation("myCalculation");
application.output("Name: " + c.getName() + ", Stored: " + c.isStored());

var allCalcs = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculations();
for (var i = 0; i < allCalcs.length; i++) {
	application.output(allCalcs[i]);
}

getDataSource()

Get the data source for this node.

Returns: String the dataSource

Sample

var nodeDataSource = solutionModel.getDataSourceNode("db:/example_data/customers").getDataSource();

getMethod(name)

Get an existing foundset method for the datasource node.

Parameters

• String name The name of the method

Returns: JSMethod the JSMethod object for the specified method name, or null if no such method exists.

Sample

var method = solutionModel.getDataSourceNode("db:/example_data/orders").newMethod("function doubleSize() { return 2*getSize(); }");

application.output('Doubled orders for this customer: '+customers_to_orders.doubleSize())

getMethods()

Gets all the foundset methods for the datasource node.

Returns: Array an array of all JSMethod objects for the data source node.

Sample

var method = solutionModel.getDataSourceNode("db:/example_data/orders").newMethod("function doubleSize() { return 2*getSize(); }");

application.output('Doubled orders for this customer: '+customers_to_orders.doubleSize())

newCalculation(code)

Creates a new calculation for the given code, the type will be the column where it could be build on (if name is a column name), else it will default to JSVariable.TEXT;

Parameters

• String code The code of the calculation, this must be a full function declaration.

Returns: JSCalculation the created JSCalculation object for the specified code with default type TEXT.

Sample

var calc = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation() { return 123; }", JSVariable.INTEGER);
var calc2 = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation2() { return '20'; }");
var calc3 = solutionModel.getDataSourceNode("db:/example_data/employees").newCalculation("function myCalculation3() { return 'Hello World!'; }",	JSVariable.TEXT);

var c = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculation("myCalculation");
application.output("Name: " + c.getName() + ", Stored: " + c.isStored());

var allCalcs = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculations();
for (var i = 0; i < allCalcs.length; i++) {
	application.output(allCalcs[i]);
}

newCalculation(code, type)

Creates a new calculation for the given code and the type, if it builds on a column (name is a column name) then type will be ignored.

Parameters

• String code The code of the calculation, this must be a full function declaration.

• Number type The type of the calculation, one of the JSVariable types.

Returns: JSCalculation the created JSCalculation object for the specified code and type.

Sample

var calc = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation() { return 123; }", JSVariable.INTEGER);
var calc2 = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation2() { return '20'; }");
var calc3 = solutionModel.getDataSourceNode("db:/example_data/employees").newCalculation("function myCalculation3() { return 'Hello World!'; }",	JSVariable.TEXT);

var c = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculation("myCalculation");
application.output("Name: " + c.getName() + ", Stored: " + c.isStored());

var allCalcs = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculations();
for (var i = 0; i < allCalcs.length; i++) {
	application.output(allCalcs[i]);
}

newMethod(code)

Creates a new foundset method with the specified code.

Parameters

• String code the specified code for the foundset method

Returns: JSMethod a JSMethod object

Sample

var method = solutionModel.getDataSourceNode("db:/example_data/orders").newMethod("function doubleSize() { return 2*getSize(); }");

application.output('Doubled orders for this customer: '+customers_to_orders.doubleSize())

removeCalculation(name)

Removes the calculation specified by name.

Parameters

• String name the name of the calculation to be removed

Returns: Boolean true if the removal was successful, false otherwise

Sample

var calc1 = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation1() { return 123; }", JSVariable.INTEGER);
var calc2 = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myCalculation2() { return '20'; }");

var c = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculation("myCalculation1");
application.output("Name: " + c.getName() + ", Stored: " + c.isStored());

solutionModel.getDataSourceNode("db:/example_data/customers").removeCalculation("myCalculation1");
c = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculation("myCalculation1");
if (c != null) {
	application.output("myCalculation could not be removed.");
}

var allCalcs = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculations();
for (var i = 0; i < allCalcs.length; i++) {
	application.output(allCalcs[i]);
}

removeMethod(name)

Removes the foundset method specified by name.

Parameters

• String name the name of the method to be removed

Returns: Boolean true if the removal was successful, false otherwise

Sample

var method1 = solutionModel.getDataSourceNode("db:/example_data/customers").newMethod("function myFoundsetMethod1() { return 123; }");
var method2 = solutionModel.getDataSourceNode("db:/example_data/customers").newCalculation("function myFoundsetMethod2() { return '20'; }");

var m = solutionModel.getDataSourceNode("db:/example_data/customers").getMethod("myFoundsetMethod1");
application.output("Name: " + m.getName());

solutionModel.getDataSourceNode("db:/example_data/customers").removeMethod("myFoundsetMethod1");
m = solutionModel.getDataSourceNode("db:/example_data/customers").getCalculation("myFoundsetMethod1");
if (m != null) { application.output("myFoundsetMethod1 could not be removed."); }

var allMethods = solutionModel.getDataSourceNode("db:/example_data/customers").getMethod();
for (var i = 0; i < allMethods; i++)
{
	application.output(allMethods[i]);
}

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