Eclipse BIRT Report Object Model (ROM)

ScriptDataSet Element

Element Overview

A data set defined in JavaScript.

Details

Display Name: Script Data Set
Since: 1.0
XML Element: script-data-set
Extends: SimpleDataSet
Extendable: Yes
Abstract: No
Name Space: Data Sets
Name Requirement: Required
Allows User Properties: Yes
Has Style: No

Property Summary

parameters
Defines the data access attributes of the list of input and/or output parameters.

Method Summary

close
Called by BIRT to close the data set.
describe
Dynamically describes the result set definition in JavaScript.
fetch
Fetches a row from the data set.
open
Opens the data set.

Inherited Properties

cachedMetaData, columnHints, comments, computedColumns, customXml, dataSetRowLimit, dataSource, displayName, displayNameID, eventHandlerClass, extends, filter, name, paramBindings, propertyMasks, refTemplateParameter, resultSetHints, rowFetchLimit, userProperties, viewAction

Inherited Methods

beforeOpen, beforeClose, onFetch, afterOpen, afterClose

Description

Represents a data set defined in JavaScript code, providing methods for opening, fetching and closing the data set. It defines the overall properties of the scripted data set including the JavaScript methods themselves and an optional result set definition.

See Also

Script Data Source element

DataSet scripting object

Property Detail

parameters Property

Defines the data access attributes of the list of input and/or output parameters.

Details

Type: List of DataSetParam Structures
Since: 1.0
Required: No
Display Name: Data set parameters
JavaScript Type:
Default Value: None
Inherited: Yes
Runtime Settable: Yes
Property Sheet Visibility: Hidden
Property Sheet Group: Top

Description

Many data sets allow parameters, which can be of input and/or output modes. For some, the user must define the parameters as part of the data set definition. For other data sets, the driver itself can provide the set of parameter definitions from the information available in a data set query. In the latter case, parameter definitions are derived data and are not stored in the parameter definition.

Some drivers refer to a parameter by position. Others can refer to a parameter by name. Also, for some data sets, the data set definition can omit parameter definitions for optional parameters not used within the report.  Not all parameter properties are required. If a property is omitted. BIRT assumes that the data set implementation can provide it at run time. If the driver cannot provide the information, then a runtime error occurs. This is an optional list of data set parameter definitions, used only when the underlying data provider cannot provide this information. When contradicting meta-data are found between those provided dynamically by a data provider and those specified in a data set definition, the data provider�s meta-data takes precedence.

See Also

DataSetParam structure

ParamBinding structure

Method Detail

close Method

Called by BIRT to close the data set.

Synopsis

None obj.close( )

Details

Since: 1.0
Context: factory
Arguments: None
Return Type: None

Description

Closes the data set. Optional.

See Also

beforeClose method

afterClose method


describe Method

Dynamically describes the result set definition in JavaScript.

Synopsis

ColumnDefn[] obj.describe( )

Details

Since: reserved
Context: factory
Arguments: None
Return Type: ColumnDefn[]

Return

The Describe method can return null, which tells BIRT to use the static definition instead. The script can access the static description using the design object within the script.

If the method returns a column array, then the array must satisfy the following constraints:

Description

Called before BIRT calls the beforeOpen method. Creates a runt-time definition of the result set columns. Returns an array of ResultSetColumn objects. Each object describes a column in the expected result set. Optional.

See Also

ResultSetColumn structure


fetch Method

Fetches a row from the data set.

Synopsis

DataRow obj.fetch( )

Details

Since: 1.0
Context: factory
Arguments: None
Return Type: DataRow

Return

Returns true if there is another row to fetch, false if there are no more rows. When the data set has returned the last row from the result set, subsequent calls to fetch should return false.

Description

Fetches a row from the data set on each call, and populates the current row available in the row property.

See Also

onFetch method

DataRow scripting object


open Method

Opens the data set.

Synopsis

None obj.open( )

Details

Since: 1.0
Context: factory
Arguments: None
Return Type: None

Description

Opens the external data set. Throws a JavaScript exception if the open fails. Often refers to report parameters or user-defined parameters for information about the data set. Optional.

See Also

beforeOpen method

afterOpen method