July 30, 2023

tMaxDBInput – Docs for ESB 7.x

tMaxDBInput

Reads a database and extracts fields based on a query.

tMaxDBInput executes a DB query with a strictly
defined order which must correspond to the schema definition. Then it passes on the
field list to the next component via a Main row link.

tMaxDBInput Standard properties

These properties are used to configure tMaxDBInput running in the Standard Job framework.

The Standard
tMaxDBInput component belongs to the Databases family.

The component in this framework is available in all Talend
products
.

Basic settings

Property type

Either Built-in or
Repository
.

 

Built-in: No property data stored
centrally.

 

Repository: Select the repository
file in which the properties are stored. The fields that follow are
completed automatically using the data retrieved.

tMaxDBInput_1.png

Click this icon to open a database connection wizard and store the
database connection parameters you set in the component Basic settings view.

For more information about setting up and storing database
connection parameters, see
Talend Studio User Guide
.

Host
name

Database server IP address

Port

Listening port number of DB server.

Database

Name of the database.

Username and
Password

DB user authentication data.

To enter the password, click the […] button next to the
password field, and then in the pop-up dialog box enter the password between double quotes
and click OK to save the settings.

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.

This
component offers the advantage of the dynamic schema feature. This allows you to
retrieve unknown columns from source files or to copy batches of columns from a source
without mapping each column individually. For further information about dynamic schemas,
see
Talend Studio

User Guide.

This
dynamic schema feature is designed for the purpose of retrieving unknown columns of a
table and is recommended to be used for this purpose only; it is not recommended for the
use of creating tables.

 

Built-in: The schema is created
and stored locally for this component only. Related topic: see

Talend Studio User
Guide
.

 

Repository: The schema already
exists and is stored in the Repository, hence can be reused. Related
topic: see
Talend Studio User
Guide
.

 

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.

Table name

Type in the table name.

Query type and
Query

Enter your DB query paying particularly attention to properly
sequence the fields in order to match the schema definition.

If using the dynamic schema
feature, the SELECT query must include the * wildcard, to retrieve all of the columns from the table
selected.

Guess Query

Click the Guess Query button to
generate the query which corresponds to your table schema in the
Query field.

Guess schema

Click the Guess schema button to
retrieve the table schema.

Advanced settings

Trim all the String/Char columns

Select this check box to remove leading and trailing whitespace
from all the String/Char columns.

Trim column

Remove leading and trailing whitespace from defined
columns.

tStat
Catcher Statistics

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

Global Variables

Global Variables

NB_LINE: the number of rows processed. This is an After
variable and it returns an integer.

QUERY: the query statement being processed. This is a Flow
variable and it returns a string.

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

This component offers the flexibility of the DB query and covers
all possible SQL queries.

Limitation

This component requires installation of its related jar files.

Related scenario


Document get from Talend https://help.talend.com
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