com.rapidminer.operator.io
Class CachedDatabaseExampleSource

java.lang.Object
  com.rapidminer.operator.Operator
      com.rapidminer.operator.io.AbstractReader<ExampleSet>
          com.rapidminer.operator.io.AbstractExampleSource
              com.rapidminer.operator.io.CachedDatabaseExampleSource

All Implemented Interfaces:

ConfigurationListener, PreviewListener, ParameterHandler, LoggingHandler

public class CachedDatabaseExampleSource
extends AbstractExampleSource

This operator reads an ExampleSet from an SQL database. The data is load from a single table which is defined with the table name parameter. Please note that table and column names are often case sensitive. Databases may behave differently here.

The most convenient way of defining the necessary parameters is the configuration wizard. The most important parameters (database URL and user name) will be automatically determined by this wizard and it is also possible to define the special attributes like labels or ids.

In contrast to the DatabaseExampleSource operator, which loads the data into the main memory, this operator keeps the data in the database and performs the data reading in batches. This allows RapidMiner to access data sets of arbitrary sizes without any size restrictions.

Please note the following important restrictions and notes:

• only manifested tables (no views) are allowed as the base for this data caching operator,
• if no primary key and index is present, a new column named RM_INDEX is created and automatically used as primary key,
• if a primary key is already present in the specified table, a new table named RM_MAPPED_INDEX is created mapping a new index column RM_INDEX to the original primary key.
• users can provide the primary key column RM_INDEX themself which then has to be an integer valued index attribute, counting starts with 1 without any gaps or missing values for all rows

Beside the new index column or the mapping table creation no writing actions are performed in the database. Moreover, data sets built on top of a cached database table do not support writing actions at all. Users have to materialize the data, change it, and write it back into a new table of the database (e.g.with the DatabaseExampleSetWriter. If the data set is large, users can employ the operator BatchProcessing for splitting up this data change task.

Author:

Ingo Mierswa

Field Summary

static java.lang.String

PARAMETER_RECREATE_INDEX

Constructor Summary

CachedDatabaseExampleSource(OperatorDescription description)

Method Summary

ExampleSet	createExampleSet() Creates (or reads) the ExampleSet that will be returned by AbstractReader.apply().
protected DatabaseHandler	getConnectedDatabaseHandler()
java.util.List<ParameterType>	getParameterTypes() Returns a list of ParameterTypes describing the parameters of this operator.
void	processFinished() Called at the end of the process.

Methods inherited from class com.rapidminer.operator.io.AbstractExampleSource

read

Methods inherited from class com.rapidminer.operator.io.AbstractReader

apply, getInputClasses, getOutputClasses

Methods inherited from class com.rapidminer.operator.Operator

addError, addValue, addWarning, apply, checkDeprecations, checkForStop, checkIO, checkProperties, clearErrorList, cloneOperator, createExperimentTree, createExperimentTree, createFromXML, createMarkedExperimentTree, createMarkedProcessTree, createProcessTree, createProcessTree, getAddOnlyAdditionalOutput, getApplyCount, getDeliveredOutputClasses, getDeprecationInfo, getDesiredInputClasses, getEncoding, getErrorList, getExperiment, getInnerOperatorsXML, getInput, getInput, getInput, getInputDescription, getIOContainerForInApplyLoopBreakpoint, getIODescription, getLog, getName, getOperatorClassName, getOperatorDescription, getParameter, getParameterAsBoolean, getParameterAsColor, getParameterAsDouble, getParameterAsFile, getParameterAsFile, getParameterAsInputStream, getParameterAsInt, getParameterAsMatrix, getParameterAsString, getParameterList, getParameters, getParameterType, getParent, getProcess, getStartTime, getStatus, getUserDescription, getValue, getValues, getXML, hasBreakpoint, hasBreakpoint, hasInput, inApplyLoop, isDebugMode, isEnabled, isExpanded, isParallel, isParameterSet, log, logError, logNote, logWarning, performAdditionalChecks, processStarts, register, registerOperator, remove, rename, resume, setApplyCount, setBreakpoint, setEnabled, setExpanded, setInput, setListParameter, setOperatorParameters, setParameter, setParameters, setParent, setUserDescription, toString, unregisterOperator, writeXML

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

PARAMETER_RECREATE_INDEX

public static final java.lang.String PARAMETER_RECREATE_INDEX

See Also:

Constant Field Values

Constructor Detail

CachedDatabaseExampleSource

public CachedDatabaseExampleSource(OperatorDescription description)

Method Detail

createExampleSet

public ExampleSet createExampleSet()
                            throws OperatorException

Description copied from class: AbstractExampleSource

Creates (or reads) the ExampleSet that will be returned by AbstractReader.apply().

Specified by:

createExampleSet in class AbstractExampleSource

Throws:

OperatorException

getConnectedDatabaseHandler

protected DatabaseHandler getConnectedDatabaseHandler()
                                               throws OperatorException,
                                                      java.sql.SQLException

Throws:

OperatorException

java.sql.SQLException

processFinished

public void processFinished()

Description copied from class: Operator

Called at the end of the process. The default implementation does nothing.

Overrides:

processFinished in class Operator

getParameterTypes

public java.util.List<ParameterType> getParameterTypes()

Description copied from class: Operator

Returns a list of ParameterTypes describing the parameters of this operator. The default implementation returns an empty list if no input objects can be retained and special parameters for those input objects which can be prevented from being consumed.

Specified by:

getParameterTypes in interface ParameterHandler

Overrides:

getParameterTypes in class Operator