tMongoDBOutput

Warning

This component will be available in the Palette of
Talend Studio on the condition that you have subscribed to one of
the Talend
solutions with Big Data.

tMongoDBOutput Properties

Component family	Big Data / MongoDB
Function	tMongoDBOutput inserts, updates, upserts or deletes documents in a MongoDB database collection based on the incoming flow from the preceding component in the Job.
Purpose	This component executes the action defined on the collection in the MongoDB database.
Basic settings	Use existing connection	Select this check box and in the Component List click the relevant connection component to reuse the connection details you already defined.
	DB Version	List of the database versions. Available when the Use existing connection check box is not selected.
	Use replica set address	Select this check box to show the Replica address table. In the Replica address table, you can define multiple MongoDB database servers for failover. Available when the Use existing connection check box is not selected.
	Server and Port	IP address and listening port of the database server. Available when the Use existing connection or Use replica set address check box is not selected.
	Database	Name of the database.
	Use SSL connection	Select this check box to enable the SSL encrypted connection. Then you need to use the tSetKeystore component in the same Job to specify the authentication information. For further information about tSetKeystore, see tSetKeystore. Note that the SSL connection is available only for the version 2.4 + of MongoDB.
	Required authentication	Select this check box to enable the database authentication.
	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. Available when the Required authentication check box is selected.
	Collection	Name of the collection in the MongoDB database.
	Drop collection if exist	Select this check box to drop the collection if it already exists.
	Action on data	The following operations are available: Insert: insert data. Update: update data. Upsert: update and insert data. Delete: delete data.
	Schema and Edit 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. 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. Click Sync columns to retrieve the schema from the previous component connected in the Job.
		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. When the schema to be reused has default values that are integers or functions, ensure that these default values are not enclosed within quotation marks. If they are, you must remove the quotation marks manually. For more details, see https://help.talend.com/display/KB/Verifying+default+values+in+a+retrieved+schema.
	Mapping	Specify the parent node for the column in the MongoDB database. Not available when the Generate JSON Document check box is selected in Advanced settings.
	Die on error	This check box is cleared by default, meaning to skip the row on error and to complete the process for error-free rows.
Advanced settings	Generate JSON Document	Select this check box for JSON configuration: Configure JSON Tree: click the […] button to open the interface for JSON tree configuration. For more information, see Configuring a JSON Tree. Group by: click the [+] button to add lines and choose the input columns for grouping the records. Remove root node: select this check box to remove the root node. Data node and Query node (available for update and upsert actions): type in the name of data node and query node configured on the JSON tree. Warning These nodes are mandatory for update and upsert actions. They are intended to enable the update and upsert actions though will not be stored in the database.
	tStatCatcher Statistics	Select this check box to collect the log data at the component level.
Global Variables	NB_LINE: the number of rows read by an input component or transferred to an output component. This is an After variable and it returns an integer. 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	tMongoDBOutput executes the action defined on the collection in the MongoDB database based on the flow incoming from the preceding component in the Job.
Log4j	The activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User Guide. For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.
Limitation	Note The “multi” parameter, which allows to update multiple documents at a time, is not supported. Therefore, if two documents have the same key, the first is always updated, but the second never will. For the update operation, the key cannot be a JSON array.

Scenario 1: Creating a collection and writing data to it

This scenario creates the collection blog and
writes post data to it.

Linking the components

Drop tMongoDBConnection, tFixedFlowInput, tMongoDBOutput, tMongoDBClose, tMongoDBInput and tLogRow
onto the workspace.
Rename tFixedFlowInput as blog_post_data, tMongoDBOutput as write_data_to_collection, tMongoDBInput as read_data_from_collection and tLogRow as show_data_from_collection.
Link tMongoDBConnection to tFixedFlowInput using the OnSubjobOk trigger.
Link tFixedFlowInput to tMongoDBOutput using a Row > Main
connection.
Link tFixedFlowInput to tMongoDBInput using the OnSubjobOk trigger.
Link tMongoDBInput to tMongoDBClose using the OnSubjobOk trigger.
Link tMongoDBInput to tLogRow using a Row > Main
connection.

Configuring the components

Double-click tMongoDBConnection to open
its Basic settings view.
From the DB Version list, select the
MongoDB version you are using.
In the Server and Port fields, enter the connection details.

In the Database field, enter the name of the MongoDB
database.

Double-click tFixedFlowInput to open its
Basic settings view.

Select Use Inline Content (delimited
file) in the Mode
area.

In the Content field, enter the data to write to the
MongoDB database, for example:

1;Andy;Open Source Outlook;Open Source,Talend;Talend, the leader of the open source world...
3;Andy;ELT Overview;ELT,Talend;Talend, the big name in the ELT circle...
2;Andy;Data Integration Overview;Data Integration,Talend;Talend, the leading player in the DI field...

1;Andy;Open Source Outlook;Open Source,Talend;Talend, the leader of the open source world...

3;Andy;ELT Overview;ELT,Talend;Talend, the big name in the ELT circle...

2;Andy;Data Integration Overview;Data Integration,Talend;Talend, the leading player in the DI field...

Double-click tMongoDBOutput to open its
Basic settings view.

Select the Use existing connection and
Drop collection if exist check
boxes.

In the Collection field, enter the name
of the collection, namely blog.
Click the […] button next to Edit schema to open the schema editor.
Click the [+] button to add five columns
in the right part, namely id, author, title, keywords and
contents, with the type as Integer and String respectively.

Click to copy all the columns to the input table.

Click Ok to close the editor.
The columns now appear in the left part of the Mapping area.

For columns author, title, keywords and
contents, enter their parent node
post. By doing so, those nodes reside
under the node post in the MongoDB
collection.
Double-click tMongoDBInput to open its
Basic settings view.

Select the Use existing connection check
box.

In the Collection field, enter the name
of the collection, namely blog.
Click the […] button next to Edit schema to open the schema editor.
Click the [+] button to add five columns,
namely id, author, title, keywords and contents, with the type as Integer and String
respectively.

Click OK to close the editor.
The columns now appear in the left part of the Mapping area.

For columns author, title, keywords and contents,
enter their parent node post so that the
data can be retrieved from the correct positions.
In the Sort by area, click the [+] button to add one line and enter id under Column.

Select asc from the Order asc or desc? column to the right of the id column. This way, the retrieved records will
appear in ascending order of the id
column.

Executing the Job

Press Ctrl+S to save the Job.
Press F6 to run the Job.
Switch to the database talend and read data from the
collection blog in the MongoDB command
line client. You can find that author,
title, keywords and contents all
reside under the node post. Meanwhile,
the records are stored in the same order as the source input.

Scenario 2: Upserting records in a collection

This scenario upserts the collection blog as an
existing record has its author changed and a new record is added. Before the upsert, the
collection blog looks like:

1;Andy;Open Source Outlook;Open Source,Talend;Talend, the leader of the open source world...
2;Andy;Data Integration Overview;Data Integration,Talend;Talend, the leading player in the DI field...
3;Andy;ELT Overview;ELT,Talend;Talend, the big name in the ELT circle...

1;Andy;Open Source Outlook;Open Source,Talend;Talend, the leader of the open source world...

2;Andy;Data Integration Overview;Data Integration,Talend;Talend, the leading player in the DI field...

3;Andy;ELT Overview;ELT,Talend;Talend, the big name in the ELT circle...

Such records can be inserted to the database following the instructions of Scenario 1: Creating a collection and writing data to it.

Linking the components

Drop tMongoDBConnection, tFixedFlowInput, tMongoDBOutput, tMongoDBClose, tMongoDBInput and tLogRow
from the Palette onto the design
workspace.
Rename tFixedFlowInput as blog_post_data, tMongoDBOutput as write_data_to_collection, tMongoDBInput as read_data_from_collection and tLogRow as show_data_from_collection.
Link tMongoDBConnection to tFixedFlowInput using the OnSubjobOk trigger.
Link tFixedFlowInput to tMongoDBOutput using a Row > Main
connection.
Link tFixedFlowInput to tMongoDBInput using the OnSubjobOk trigger.
Link tMongoDBInput to tMongoDBClose using the OnSubjobOk trigger.
Link tMongoDBInput to tLogRow using a Row > Main
connection.

Configuring the components

Double-click tMongoDBConnection to open
its Basic settings view.
From the DB Version list, select the
MongoDB version you are using.
In the Server and Port fields, enter the connection details.

In the Database field, enter the name of the MongoDB
database.

Double-click tFixedFlowInput to open its
Basic settings view.

Select Use Inline Content (delimited
file) in the Mode
area.

In the Content field, enter the data for upserting the
MongoDB database, for example:

1;Andy;Open Source Outlook;Open Source,Talend;Talend, the leader of the open source world...
2;Andy;Data Integration Overview;Data Integration,Talend;Talend, the leading player in the DI field...
3;Anderson;ELT Overview;ELT,Talend;Talend, the big name in the ELT circle...
4;Andy;Big Data Bang;Big Data,Talend;Talend, the driving force for Big Data applications...

1;Andy;Open Source Outlook;Open Source,Talend;Talend, the leader of the open source world...

2;Andy;Data Integration Overview;Data Integration,Talend;Talend, the leading player in the DI field...

3;Anderson;ELT Overview;ELT,Talend;Talend, the big name in the ELT circle...

4;Andy;Big Data Bang;Big Data,Talend;Talend, the driving force for Big Data applications...

As shown above, the 3rd record has its author changed and the 4th record
is new.

Double-click tMongoDBOutput to open its
Basic settings view.

Select the Use existing connection and
Die on error check boxes.

In the Collection field, enter the name
of the collection, namely blog.

Select Upsert from the Action on data list.
Click the […] button next to Edit schema to open the schema editor.
Click the [+] button to add five columns
in the right part, namely id, author, title, keywords and
contents, with the type as Integer and String respectively.

Click to copy all the columns to the input table.

Click Ok to close the editor.
In the Advanced Settings view, select the
Generate JSON Document check
box.

Select the Remove root node check box.

In the Data node and Query node fields, enter “data” and “query”.
Click the […] button next to Configure JSON Tree to open the configuration
interface.
Right-click the node rootTag and select
Add Sub-element from the contextual
menu.

In the dialog box that appears, type in data for the Data
node:

Click OK to close the window.

Repeat this operation to define query
as the Query node.

Right-click the node data and select
Set As Loop Element from the contextual
menu.

Warning

These nodes are mandatory for update and upsert actions. They are
intended to enable the update and upsert actions though will not be
stored in the database.
Select all the columns under the Schema
list and drop them to the data node.

In the window that appears, select Create as
sub-element of target node.

Click OK to close the window.

Repeat this operation to drop the id
column from the Schema list under the
Query node.
Right-click the node id under data and select Add
Attribute from the contextual menu.

In the dialog box that appears, type in type as the attribute name:

Click OK to close the window.

Right-click the node @type under
id and select Set A Fix Value from the contextual menu.

In the dialog box that appears, type in integer as the attribute value, ensuring the id values are stored as integers in the
database.

Click OK to close the window.

Repeat this operation to set this attribute for the id node under Query.

Click OK to close the JSON Tree
configuration interface.
Double-click tMongoDBInput to open its
Basic settings view.

Select the Use existing connection check
box.

In the Collection field, enter the name
of the collection, namely blog.

Click the […] button next to Edit schema to open the schema editor.

Click the [+] button to add five columns,
namely id, author, title, keywords and contents, with the type as Integer and String
respectively.

Click OK to close the editor.

The columns now appear in the left part of the Mapping area.

For columns author, title, keywords and contents,
enter their parent node post so that the
data can be retrieved from the correct positions.
Double-click tLogRow to open its
Basic settings view.

In the Mode area, select Table (print values in cells of a table for
better display.