tCassandraOutputBulk Standard properties - 7.3

Property type

Either Built-In or Repository.

Built-In: No property data stored centrally.

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

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.

Built-In: You create and store the schema locally for this component only.

Repository: You have already created the schema and stored it in the Repository. You can reuse it in various projects and Job designs.

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 information, see the related description of retrieving table schemas in Talend Studio User Guide.

Table type

Select the type of the data model to be used for the table to be created. It can be CQL (actually CQL3) or non-CQL (the legacy thrift-based API of Cassandra before CQL3).

This drop-down list is available only when the DB version you are using is Cassandra 2.0.0 (deprecated). For the Cassandra versions later than 2.0.0, CQL becomes the only model used by this component and so this list is no longer available.

DB Version

Select the Cassandra version you are using.

Keyspace

Type in the name of the keyspace into which you want to write the SSTable.

Column family

Type in the name of the column family into which you want to write the SSTable.

Partitioner

Select the partitioner which determines how data is distributed across the Cassandra cluster.

• Random

• Murmur3

• Order preserving: not recommended because it assumes keys are UTF8 strings.

For more information about the partitioner, see http://wiki.apache.org/cassandra/Partitioners.

Schema statement

Enter the statement to define the schema of the column family to be used or to be created on the fly.

• This statement is a Cassandra prepared statement, which stores query results locally in the SSTable directory you define with this component before sending them to the server. For further information about the prepared statements, see Prepared statements.

• A Cassandra column family is a container for a collection of rows of records that have a similar kind. Its schema must contain strictly the same columns as the component schema you have defined, that is to say, the column names and the order of the columns in both the schemas must be identical.

create table ks.tb (id int, name text, birthday timestamp, primary key(id, birthday)) with clustering order by (birthday desc)

For further information about a column family, see Standard column family.

This field is available only when the version of your Cassandra database is later than 2.0.0. When it is 2.0.0 (deprecated), it is available only when you have selected CQL from the Table type drop-down list.

Insert statement

Enter the statement to instruct how to write the data from the input flow into the columns of the column family to be used.

This statement is a Cassandra prepared statement, which stores query results locally in the SSTable directory you define with this component before sending them to the server. For further information about the prepared statements, see Prepared statements.

insert into ks.tb (id, name, birthday) values (?, ?, ?)

This field is available only when the version of your Cassandra database is later than 2.0.0. When it is 2.0.0 (deprecated), it is available only when you have selected CQL from the Table type drop-down list.

Column name comparator

Select the data type for the column names, which is used to sort columns. This list is not available when the data model to be used is CQL3.

For more information about the comparators, see http://www.datastax.com/docs/1.1/ddl/column_family#about-data-types-comparators-and-validators.

SSTable directory

Specify the local directory for the SSTable. Note that the complete path to the SSTable will be the local directory appended by the specified keyspace name and column family name.

For example, if you set the local directory to /home/talend/sstable, and specify testk as the keyspace name and testc as the column family name, the complete path to the SSTable will be /home/talend/sstable/testk/testc/.

Buffer size

Specify what size the SSTable must reach before it is written into Cassandra.

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

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 rule

This component always needs an incoming link.