tDeltaLakeInput Standard properties

Select the desired database type from the list and click Apply.

Property Type

Select the way the connection details will be set.

• Built-In: The connection details will be set locally for this component. You need to specify the values for all related connection properties manually.

• Repository: The connection details stored centrally in Repository > Metadata will be reused by this component.

  You need to click the [...] button next to it and in the pop-up Repository Content dialog box, select the connection details to be reused, and all related connection properties will be automatically filled in.

This property is not available when other connection component is selected from the Connection Component drop-down list.

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 Centralizing database metadata.

Connection Component

Select the component that opens the database connection to be reused by this component.

JDBC URL

The JDBC URL of the Delta Lake database to be used, which begins with jdbc:spark:// (already presented). If you have installed the 8.0.1-R2023-05 Talend Studio Monthly update or a later one delivered by Talend, the JDBC URL of the Delta Lake database begins with jdbc:databricks// (already presented).

See section Configure JDBC URL at JDBC and ODBC drivers and configuration parameters for related information.

Drivers

Complete this table to load the driver JARs needed. To do this, click the [+] button under the table to add as many rows as needed, each row for a driver JAR, then select the cell and click the [...] button at the right side of the cell to open the Module dialog box from which you can select the driver JAR to be used. The driver JAR SparkJDBC42-2.6.14.1018.jar is used for the Delta Lake databases (already presented). If you have installed the 8.0.1-R2023-05 Talend Studio Monthly update or a later one delivered by Talend, the databricks-jdbc-{version_number}.jar driver will be used (already presented).

For more information, see Importing a database driver.

Driver Class

Enter the class name for the specified driver between double quotation marks. For the SparkJDBC42-2.6.14.1018.jar driver, the name to be entered is com.simba.spark.jdbc.Driver (already presented). If you have installed the 8.0.1-R2023-05 Talend Studio Monthly update or a later one delivered by Talend, the databricks-jdbc-{version_number}.jar driver will be used and the driver class to be entered is com.databricks.client.jdbc.Driver (already presented).

User Id and Password

The database user authentication data. See section Username and password authentication at JDBC and ODBC drivers and configuration parameters for related information.

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

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.

• 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.

Click Edit schema to make changes to the schema. If you make changes, the schema automatically becomes built-in.

• 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.

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 Dynamic schema.

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.

Table Name

The name of the table from which data will be retrieved.

Query Type and Query

Specify the database query statement paying particularly attention to the properly sequence of the fields which must correspond to the schema definition.

• Built-In: Fill in the query statement in the Query field manually or click the [...] button next to the Query field to build the statement graphically using the SQLBuilder.

• Repository: Select the relevant query stored in the Repository by clicking the [...] button next to it and in the pop-up Repository Content dialog box, select the query to be used, and the Query field will be automatically filled in.

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 this button to generate query in the Query field based on the defined table and schema.

Guess Schema

Click this button to generate schema columns based on the query defined in the Query field.

Specify a data source alias

Select this check box and in the Data source alias field displayed, specify the alias of a data source created on Talend Runtime side to use the shared connection pool defined in the data source configuration. This option works only when you deploy and run your Job in Talend Runtime.

This property is not available when other connection component is selected from the Connection Component drop-down list.

Use cursor

Select this check box to specify the number of rows you want to work with at any given time. This option optimises performance.

Trim all the String/Char columns

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

Check column to trim

Select the check box for corresponding column to remove leading whitespace and trailing whitespace from it.

This property is not available when the Trim all the String/Char columns check box is selected.

Enable Mapping File for Dynamic

Select this check box to use the specified metadata mapping file when reading data from a dynamic type column. This check box is cleared by default.

With this check box selected, you can specify the metadata mapping file to use by selecting a type of database from the Mapping File drop-down list.

For more information about metadata mapping files, see Accessing mapping files and defining type mappings.

Select this check box if you want to query the database using a prepared statement. In the Set PreparedStatement Parameters table displayed, specify the value for each parameter represented by a question mark ? in the SQL statement defined in the Query field.

• Parameter Index: the position of the parameter in the SQL statement.

• Parameter Type: the data type of the parameter.

• Parameter Value: the value of the parameter.

For a related use case of this property, see Using PreparedStatement objects to query data.

Allow special character in Dynamic table name

Select this option to use the actual column names of the input table in the dynamic column. This option prevents special characters (for example, $) in the input table column names from being converted into _ in the dynamic column.

This option is selected by default.

tStatCatcher Statistics

Select this check box to gather the Job processing metadata at the Job level as well as at each component level.

ERROR_MESSAGE

The error message generated by the component when an error occurs. This is an After variable and it returns a string.

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.

Usage rule

This component covers all possible SQL queries for any database using a Delta Lake connection.

Click the [+] button to add a row in the table and fill the Code field with a context variable to choose your database connection dynamically from multiple connections planned in your Job. This feature is useful when you need to access database tables having the same data structure but in different databases, especially when you are working in an environment where you cannot change your Job settings, for example, when your Job has to be deployed and executed independent of Talend Studio.

For examples on using dynamic parameters, see Reading data from databases through context-based dynamic connections and Reading data from different MySQL databases using dynamically loaded connection parameters. For more information on Dynamic settings and context variables, see Dynamic schema and Creating a context group and define context variables in it.