tCassandraInput Standard properties - 7.2

Cassandra

author
Talend Documentation Team
EnrichVersion
7.2
EnrichProdName
Talend Big Data
Talend Big Data Platform
Talend Data Fabric
Talend Open Studio for Big Data
Talend Real-Time Big Data Platform
task
Data Governance > Third-party systems > Database components > Cassandra components
Data Quality and Preparation > Third-party systems > Database components > Cassandra components
Design and Development > Third-party systems > Database components > Cassandra components
EnrichPlatform
Talend Studio

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

The Standard tCassandraInput component belongs to the Big Data and the Databases NoSQL families.

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

Basic settings

Property type

Either Built-In or Repository.

Built-In: No property data stored centrally.

Repository: Select the repository file where the properties are stored.

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 Cassandra version you are using.

API type

This drop-down list is displayed only when you have selected the 2.0 version (deprecated) of Cassandra from the DB version list. From this API type list, you can either select Datastax to use CQL 3 (Cassandra Query Language) with Cassandra, or select Hector (deprecated) to use CQL 2.

Note that the Hector API is deprecated along with the support for Cassandra V2.0.

Along with the evolution of the CQL commands, the parameters to be set in the Basic settings view varies.

Host

Hostname or IP address of the Cassandra server.

Port

Listening port number of the Cassandra server.

Required authentication

Select this check box to provide credentials for the Cassandra authentication.

This check box appears only if you do not select the Use existing connection check box.

Username

Fill in this field with the username for the Cassandra authentication.

Password

Fill in this field with the password for the Cassandra 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.

Keyspace

Type in the name of the keyspace from which you want to read data.

Column family

Type in the name of the column family from which you want to read data.

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.

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.

Query

Enter the query statements to be used to read data from the Cassandra database.

By default, the query is not case-sensitive. This means that at runtime, the column names you put in the query are always taken in lower case. If you need to make the query case-sensitive, put the column names in double quotation marks.

The [...] button next to this field allows you to generate the sample code that shows what the pre-defined variables are for the data to be read and how these variables can be used.

This feature is available only for the Datastax API of Cassandra 2.0 (deprecated) or a later version.

Column family type

Standard: Column family is of standard type.

Super: Column family is of super type.

Include key in output columns

Select this check box to include the key of the column family in output columns.

  • Key column: select the key column from the list.

Row key type

Select the appropriate Talend data type for the row key from the list.

Row key Cassandra type

Select the corresponding Cassandra type for the row key from the list.

Warning:

The value of the Default option varies with the selected row key type. For example, if you select String from the Row key type list, the value of the Default option will be UTF8.

For more information about the mapping table between Cassandra type and Talend data type, see Mapping tables between Cassandra type and Talend data type.

Include super key output columns

Select this check box to include the super key of the column family in output columns.

  • Super key column: select the desired super key column from the list.

This check box appears only if you select Super from the Column family type drop-down list.

Super column type

Select the type of the super column from the list.

Super column Cassandra type

Select the corresponding Cassandra type for the super column from the list.

For more information about the mapping table between Cassandra type and Talend data type, see Mapping tables between Cassandra type and Talend data type.

Specify row keys

Select this check box to specify the row keys of the column family directly.

Row Keys

Type in the specific row keys of the column family in the correct format depending on the row key type.

This field appears only if you select the Specify row keys check box.

Key start

Type in the start row key of the correct data type.

Key end

Type in the end row key of the correct data type.

Key limit

Type in the number of rows to be read between the start row key and the end row key.

Specify columns

Select this check box to specify the column names of the column family directly.

Columns

Type in the specific column names of the column family in the correct format depending on the column type.

This field appears only if you select the Specify columns check box.

Columns range start

Type in the start column name of the correct data type.

Columns range end

Type in the end column name of the correct data type.

Columns range limit

Type in the number of columns to be read between the start column and the end column.

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

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

Usage rule

This component always needs an output link.