Component family |
Big Data / CouchDB | |
Basic 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. The schema is either Built-In or stored remotely in the Repository. Since version 5.6, both the Built-In mode and the Repository mode are available in any of the Talend solutions. Click Edit schema to make changes to the schema. If the current schema is of the Repository type, three options are available:
The columns in the schema may vary depending on your configuration:
|
Connection |
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 |
Select the CouchDB version that you are using. | |
Server |
Hostname or IP address of the CouchDB server. | |
Port |
Listening port number of the CouchDB server. | |
Database |
Specify the database that you want to use. | |
Authentication |
Required authentication |
Select this check box to provide credentials for the CouchDB authentication.
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. |
Replication |
Use trigger replication |
Select this check box to trigger replication between databases. WarningThis check box appears only if you do not select the Use an existing connection check box. |
Target DB name |
Specify the target database to which the documents will be copied. It can be a local database name or a remote database URL. | |
Continuous |
Select this check box to continue a replication upon the server restart. | |
Create target DB |
Select this check box to create the target database if it does not exist. | |
IS Canceled |
Select this check box to cancel the existing replication between the specified source database and target database at the end of the Job. | |
Querying options |
Query by view |
Select this check box to specify query conditions based on a view which involves one map function and one optional reduce function. |
Design Document |
Type in the name of the design document from which you want to read data. | |
Action on design document |
Select the operation you want to perform on the design document of interest:
| |
View |
Type in the name of the view from which you want to read data. | |
Action on view |
Select the operation you want to perform on the view of interest:
| |
Map |
Enter the map function in this field. WarningThis field appears only if you select Create view from the Action on view drop-down list. | |
Reduce |
Enter the reduce function in this field. WarningThis field appears only if you select Create view from the Action on view drop-down list and select the Is reduce check box. | |
Start key |
Type in the start key. | |
End key |
Type in the end key. | |
Start key docid |
Type in the start key document id. | |
End key docid |
Type in the end key document id. | |
Is reduce |
Select this check box to make the reduce function take effect. | |
Group |
Select this check box to make the reduce function reduce to a set of distinct keys or to a single result row. WarningThis check box appears only if you select the Is reduce check box. | |
Group level |
Enter the specific group level in this field after you select the Group check box. | |
Include docs |
Select this check box to include the document which emitted each view entry. WarningThis check box appears only if you do not select the Is reduce check box. | |
Descending |
Select this check box to reverse the query order. | |
Add options |
Select this check box to add more query options and define the parameters as needed. | |
Extract JSON field |
Select this check box to extract the desired JSON data based on XPath query. | |
JSON field |
List of JSON fields to be extracted. WarningMake sure you select a JSON field whose value is a JSON document. Otherwise, errors may occur unexpectedly. | |
Loop XPath query |
Node within the JSON field, on which the loop is based. | |
Mapping |
Schema output column: schema defined to hold the data extracted from the JSON field. XPath query: XPath query to specify the node within the JSON field to be extracted. Get Nodes: select this check box if you need to get values from a nested node within the JSON field. | |
Limit | Enter the maximum number of rows to process. | |
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 |
tStatCatcher Statistics |
Select this check box to gather the Job processing metadata at the Job level as well as at each 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 |
This component always needs an output link. | |
Log4j | If you are using a subscription-based version of the Studio, 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 |
n/a |