tELTHiveInput - 6.3

Talend Open Studio for Big Data Components Reference Guide

EnrichVersion
6.3
EnrichProdName
Talend Open Studio for Big Data
task
Data Governance
Data Quality and Preparation
Design and Development
EnrichPlatform
Talend Studio

The three ELT Hive components are closely related, in terms of their operating conditions. These components should be used to handle Hive DB schemas to generate Insert statements, including clauses, which are to be executed in the DB output table defined.

Function

This component provides, for the tELTHiveMap component that follows, the input schema of the Hive table to be used.

Purpose

This component helps to replicate the schema, which the tELTHiveMap component that follows will use, of the input Hive table.

tELTHiveInput properties

Component family

ELT/Map/Hive

 

 Basic settings

Schema

A schema is a row description. It defines the number of fields to be processed and passed on to the next component. The schema is either Built-in or stored remotely in the Repository.

 

 

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.

Since version 5.6, both the Built-In mode and the Repository mode are available in any of the Talend solutions.

 

Edit schema

Click Edit schema to make changes to the schema. If the current schema is of the Repository type, three options are available:

  • View schema: choose this option to view the schema only.

  • Change to built-in property: choose this option to change the schema to Built-in for local changes.

  • Update repository connection: choose this option to change the schema stored in the repository and decide whether to propagate the changes to all the Jobs upon completion. If you just want to propagate the changes to the current Job, you can select No upon completion and choose this schema metadata again in the [Repository Content] window.

 

Default table name

Enter the name of the input table to be used.

 

Default schema name

Enter the name of the database schema to which the input table to be used is related.

 Advanced settings

tStat Catcher Statistics

Select this check box to collect log data at the component level.

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

tELTHiveMap is used along with a tELTHiveInput and tELTHiveOutput. Note that the Output link to be used with these components must correspond strictly to the syntax of the table name.

If the Studio used to connect to a Hive database is operated on Windows, you must manually create a folder called tmp in the root of the disk where this Studio is installed.

Note

The ELT components do not handle actual data flow but only schema information.

Related scenario

For a related scenario, see Scenario: Joining table columns and writing them into Hive