Databricks - Select

Overview

You can use this Snap to fetch data from a database by providing the table name from a Databricks Lakehouse Platform (DLP) instance. You can read and process this output data from a downstream Snap.

Read-type Snap
Does not support Ultra Tasks

Prerequisites

Valid access credentials to a DLP instance with adequate access permissions to perform the action in context.
Valid access to the external source data in one of the following: Azure Blob Storage, ADLS Gen2, DBFS, GCP, AWS S3, or another database (JDBC-compatible).

Limitations

Snaps in the Databricks Snap Pack do not support array, map, and struct data types in their input and output documents.

Snap views


View	Description	Examples of upstream and downstream Snaps
Input	A JSON document containing the input values for the Snap’s configuration.	Mapper Copy Databricks - Bulk Load
Output	The default output view contains the data fetched by running the SELECT statement on the source location. A second view can be added to show the metadata for the table as a Document. The metadata document can then be fed into the second input view of Databricks - Merge Into or Bulk Load Snaps so that the table is created in Databricks with a similar schema as the source table.	Databricks - Insert Mapper Router
Error	Error handling is a generic way to handle errors without losing data or failing the Snap execution. You can handle the errors that the Snap might encounter when running the pipeline by choosing one of the following options from the When errors occur list under the Views tab. The available options are: Stop Pipeline Execution Stops the current pipeline execution when an error occurs. Discard Error Data and Continue Ignores the error, discards that record, and continues with the remaining records. Route Error Data to Error View Routes the error data to an error view without stopping the Snap execution. Learn more about Error handling in Pipelines.

Snap settings

Legend:

Expression icon (): Allows using pipeline parameters to set field values dynamically (if enabled). SnapLogic Expressions are not supported. If disabled, you can provide a static value.
SnapGPT (): Generates SnapLogic Expressions based on natural language using SnapGPT. Learn more.
Suggestion icon (): Populates a list of values dynamically based on your Snap configuration. You can select only one attribute at a time using the icon. Type into the field if it supports a comma-separated list of values.
Upload : Uploads files. Learn more.

Learn more about the icons in the Snap settings dialog.


Field / Field set	Type	Description
Label	String	Required. Specify a unique name for the Snap. Modify this to be more appropriate, especially if more than one of the same Snaps is in the pipeline. Default value: Databricks - Select Example: DLP Select
Use unity catalog	Checkbox	Select this checkbox to use the Unity catalog to access data from the catalog. Default status: Deselected
Catalog name	String/Expression/ Suggestion	Appears when you select Use unity catalog. Specify the name of the catalog for using the unity catalog. Default value: hive_metastore Example: xyzcatalog
Database name	String/Expression/ Suggestion	Enter your DLP database name for the SELECT statement to read the data from. Default value: N/A Example: SalesDB
Table name	String/Expression/ Suggestion	Required. Enter your table name for the SELECT statement to read the data from. Default value: N/A Example: leads_to_sales_conversion
Where clause	String/Expression/ Suggestion	Specify the WHERE clause (condition) for the SELECT statement to apply while retrieving the data from the DLP table. Default value: N/A Example: LEAD_CITY=Delware
Order by	You can use this field set to define the order in which the retrieved rows are populated in the output. Click the Add fieldset row icon and specify one column name in each row to define your sort order.
Column names	String/Expression/ Suggestion	Click the Suggest icon and select a column name from the suggested list of column names in the table specified above. Note: If you do not specify a sort order in this fieldset, the Snap returns data in the same order as the DLP table. Default value: None. Example: LEAD_REGION
Limit rows	String/Expression	Specify the number of rows of data you want the Snap to retrieve from the table. Note: If you do not specify a limit in this fieldset, the Snap returns entire data in the the DLP table during execution. See Snap Execution field below for the limits during Pipeline validation. Default value: None. Example: 100
Output fields	You can use this fieldset to define the list of columns to be retrieved in the output. Click the Add fieldset row icon and specify one column name in each row.
Output field	String/Expression/ Suggestion	Click the Suggest icon and select a column name from the suggested list of column names in the table specified above. Note: If you do not specify any output fields, the Snap returns data from all the columns in the DLP table. Default value: None. Example: LEAD_EXP_VALUE
Fetch Output Fields In Schema	Checkbox	Select this checkbox to retrieve schema information from the table for only the output fields specified above. If not selected, the Snap retrieves schema information from all fields available in the table. Default status: Deselected Example: Not selected
Pass through	Checkbox	Select this checkbox to include the input document as-is under the `original` key of this Snap's output. Default status: Selected Example: Not selected
Ignore empty result	Checkbox	Select this checkbox to prevent the Snap from writing any document to its output view when no records are retrieved for the specified Snap configuration. Note: When no records are retrieved and the Pass through checkbox is selected, the Snap output contains the input document in the `original` key. Default status: Deselected Example: Selected
Match data types	Checkbox	With at least one output field selected in the Output fields fieldset, select this checkbox to match the data types of the columns with those retrieved when no output field is specified (as in `SELECT * FROM...` ). The output preview will be in the same format as the one when the statement `SELECT * FROM <specified_table>` is run and all the contents of the table are displayed. Default status: Deselected Example: Selected
Number of Retries	Integer/Expression	Specifies the maximum number of retry attempts when the Snap fails to write. Note: If the value is larger than 0, the Snap first downloads the target file into a temporary local file. If any error occurs during the download, the Snap waits for the time specified in the Retry interval and attempts to download the file again from the beginning. When the download is successful, the Snap streams the data from the temporary file to the downstream Pipeline. All temporary local files are deleted when they are no longer needed. Ensure that the local drive has sufficient free disk space to store the temporary local file. Minimum value: 0 Default value: 3 Example: 0
Retry Interval (seconds)	Integer/Expression	Specifies the minimum number of seconds the Snap must wait before each retry attempt. Minimum value: 1 Default value: 1 Example: 3
Staging Mode	Dropdown list	Select this property to specify the location where the in-flight records should be stored while using the Retry option. Options available are: On disk: The records are stored on the disk. In Memory: The records are stored in the internal memory. Default value: In Memory Example: On disk
Manage Queued Queries	Dropdown list	Select this property to determine whether the Snap should continue or cancel the execution of the queued Databricks SQL queries when you stop the Pipeline. Note: If you select Cancel queued queries when pipeline is stopped or if it fails, then the read queries under execution are cancelled, whereas the write type of queries under execution are not cancelled. Databricks internally determines which queries are safe to be cancelled and cancels those queries. Warning: Due to an issue with DLP, aborting an ELT Pipeline validation (with preview data enabled) causes only those SQL statements that retrieve data using bind parameters to get aborted while all other static statements (that use values instead of bind parameters) persist. For example, `select * from a_table where id = 10` will not be aborted while `select * from test where id = ?` gets aborted. To avoid this issue, ensure that you always configure your Snap settings to use bind parameters inside its SQL queries. Default value: Continue to execute queued queries when pipeline is stopped or if it fails. Example: Cancel queued queries when pipeline is stopped or if it fails
Snap execution	Dropdown list	Choose one of the three modes in which the Snap executes. Available options are: Validate & Execute: Performs limited execution of the Snap and generates a data preview during pipeline validation. Subsequently, performs full execution of the Snap (unlimited records) during pipeline runtime. Execute only: Performs full execution of the Snap during pipeline execution without generating preview data. Disabled: Disables the Snap and all Snaps that are downstream from it. Default value: Execute only Example: Validate & Execute

Troubleshooting


Error	Reason	Resolution
Missing property value	You have not specified a value for the required field where this message appears.	Ensure that you specify valid values for all required fields.

Examples

Inserting data from a Databricks table into a Snowflake table