tSchemaComplianceCheck MapReduce properties - 7.0

Validation

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Talend Documentation Team
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7.0
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Talend Big Data
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Data Governance > Third-party systems > Data Quality components > Validation components
Data Quality and Preparation > Third-party systems > Data Quality components > Validation components
Design and Development > Third-party systems > Data Quality components > Validation components
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Talend Studio

These properties are used to configure tSchemaComplianceCheck running in the MapReduce Job framework.

The MapReduce tSchemaComplianceCheck component belongs to the Data Quality family.

The component in this framework is available in all subscription-based Talend products with Big Data and Talend Data Fabric.

Basic settings

Base Schema and Edit schema

A schema is a row description. It defines the number of fields (columns) to be processed and passed on to the next component. When you create a Spark Job, avoid the reserved word line when naming the fields.

It describes the structure and nature of your data to be processed as it is.

 

Built-In: You create and store the schema locally for this component only. Related topic: see Talend Studio User Guide.

 

Repository: You have already created the schema and stored it in the Repository. You can reuse it in various projects and Job designs. Related topic: see Talend Studio User Guide.

Check all columns from schema

Select this option to carry out all checks on all columns against the base schema.

Custom defined

Select this option to carry out particular checks on particular columns. When this option is selected, the Checked Columns table shows.

Checked Columns

In this table, define what checks are to be carried out on which columns.

 

Column: Displays the columns names.

 

Type: Select the type of data each column is supposed to contain. This validation is mandatory for all columns.

 

Date pattern: Define the expected date format for each column with the data type of Date.

 

Nullable: Select the check box in an individual column to define the column to be nullable, that is, to allow empty rows in this column to go to the output flow regardless of the base schema definition. To define all columns to be nullable, select the check box in the table header.

 

Undefined or empty: Select the check box in an individual column to reject empty rows in this column while the column is not nullable in the base schema definition. To carry out this verification on all the columns, select the check box in the table header.

 

Max length: Select the check box in an individual column to verify the data length of the column against the length definition of the base schema. To carry out this verification on all the columns, select the check box in the table header.

Use another schema for compliance check

Define a reference schema as you expect the data to be, in order to reject the non-compliant data.

It can be restrictive on data type, null values, and/or length.

Trim the excess content of column when length checking chosen and the length is greater than defined length

With any of the three modes of tSchemaComplianceCheck, select this check box to truncate the data that exceeds the length specified rather than reject it.

Note:

This option is applicable only on data of String type.

Advanced settings

Use Fastest Date Check

Select this check box to perform a fast date format check using the TalendDate.isDate() method of the Talend Date system routine if Date pattern is not defined. For more information about routines, see Talend Studio User Guide.

Ignore TimeZone when Check Date

Select this check box to ignore the time zone setup upon date check.

Not available when the Check all columns from schema mode is selected.

Treat all empty string as NULL

Select this check box to treat any empty fields in any columns as null values, instead of empty strings.

By default, this check box is selected. When it is cleared, the Choose Column(s) table shows to let you select individual columns.

Global Variables

Global Variables

ERROR_MESSAGE: the error message generated by the component when an error occurs. This is an After variable and it returns a string. This variable functions only if the Die on error check box is cleared, if the component has this check box.

A Flow variable functions during the execution of a component while an After variable functions after the execution of the component.

To fill up a field or expression with a variable, press Ctrl + Space to access the variable list and choose the variable to use from it.

For further information about variables, see Talend Studio User Guide.

Usage

Usage rule

In a Talend Map/Reduce Job, this component is used as an intermediate step and other components used along with it must be Map/Reduce components, too. They generate native Map/Reduce code that can be executed directly in Hadoop.

It does not support data of the Object and the List types.

For further information about a Talend Map/Reduce Job, see the sections describing how to create, convert and configure a Talend Map/Reduce Job of the Talend Open Studio for Big Data Getting Started Guide .

Note that in this documentation, unless otherwise explicitly stated, a scenario presents only Standard Jobs, that is to say traditional Talend data integration Jobs, and non Map/Reduce Jobs.