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Snap type:

Read

Description:

The Teradata Select Snap allows you to fetch data from an Teradata database by providing a table name and configuring the connection.  The Snap produces the records from the database on its output view which can then be processed by a downstream Snap. 

JSON paths can be used in a query and will have values from an incoming document substituted into the query. However, documents missing values for a given JSON path will be written to the Snap's error view. After a query is executed, the query's results are merged into the incoming document overwriting any existing keys' values. The original document is output if there are no results from the query.

Queries produced by the Snap have the format:

Code Block
SELECT TOP [limit] * FROM [table] WHERE [where clause] ORDER BY [ordering]


If more powerful functionality is desired, then the Execute Snap should be used.

Expected upstream Snaps: A dynamic where clause can be defined by providing values upstream. Such as the Mapper Snap can provide constants, pipeline parameters mapped into variables which then can be used in the where clause or even in the table/schema properties.
Expected downstream Snaps: The Snap will output one document for every record retrieved, hence any document processing snap can be used down stream.
Expected input: Document that provides values for one or more properties of the snap or simply for pass through purpose.
Expected output: Document for each record retrieved.

Info

The where clause can only use variables, no constants or pipeline parameters. 
A good example for a where clause is: SALARY =$SALARY (here we use the SALARY variable of the input document)
A bad example for a where clause is: SALARY = _param (this will not work since we do not evaluate pipeline parameters during prepared statement execution, instead an upstream mapper needs to be used that maps _param into $SALARY) 


Prerequisites:

[None]

Support and limitations:

Works in Ultra

Pipelines

Tasks.

Account: 

This Snap uses account references created on the Accounts page of SnapLogic Manager to handle access to this endpoint. See Configuring Teradata Database Accounts for information on setting up this type of account.

Views:


InputThis Snap has one output view by default and produces one Document for each record in the table.  A second view can be added to dump out the metadata for the table as a Document. 
Output

This Snap has at most one error view and produces zero or more Document(s) in the view.

ErrorThis Snap has at most one error view and produces zero or more Document(s) in the view.


Settings

Label

Required. The name for the Snap. You can modify this to be more specific, especially if you have more than one of the same Snap in your pipeline.

Schema name

The database schema name. In case it is not defined, then the suggestion for the table name will retrieve all tables names of all schemas. The property is suggest-able and will retrieve available database schemas during suggest values.

Example: SYS
Default value: None 

Table name

Name of table to execute select query on.

Example: people

Default value: None 

 

Where clause  

Where clause of select statement. This supports document value substitution (such as $person.firstname will be substituted with the value found in the incoming document at the path). However, you may not use a value substitution after "IS" or "is" word. Please see the examples below.

Examples: 

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Without using expressions

Using expressions

  • "EMPNO=$EMPNO and ENAME=$EMPNAME"

  • email = $email 

  • emp=$emp

  • "emp='" + $emp + "'"

  • "EMPNO=" + $EMPNO + " and ENAME='" + $EMPNAME+ "'"


Warning
titleCaution

Using expressions that join strings together to create SQL queries or conditions has a potential SQL injection risk and is hence unsafe. Ensure that you understand all implications and risks involved before using concatenation of strings with '=' Expression enabled. 


Order by columns

Enter in the columns in order to order by. The default database sort order will be used.

Example: 

name

email

Default value: None 

Limit offset


Starting row for the query

Example: 0

Default value: None 

Output fields

Enter or select output field names for SQL SELECT statement. To select all fields, leave it at default.

Example: email, address, first, last, etc.

Default value:  None

Fetch Output Fields In Schema

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Cassandra - Select
Cassandra - Select
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Default value: Not selected

Pass through

If checked, the input document will be passed through to the output view under the key 'original'.

Default value: Selected 

Ignore empty result

 If checked, no document will be written to the output view when the SELECT operation does not produces any result. If this property is unchecked and the Pass through property is checked, the input document will be passed through to the output view.

Default value: False

Auto commit

Select one of the options for this property to override the state of the Auto commit property on the account. The Auto commit at the Snap-level has three values: True, False, and Use account setting. The expected functionality for these modes are:

  •  True - The Snap will execute with auto-commit enabled regardless of the value set for Auto commit in the Account used by the Snap.
  •  False - The Snap will execute with auto-commit disabled regardless of the value set for Auto commit in the Account used by the Snap.
  • Use account setting - The Snap will execute with Auto commit property value inherited by the Account used by the Snap.

Default value: Use account setting

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Snap Execution

pageAnaplan Read Multiexcerpt include macronameSnap_Execution_IntroducedpageAnaplan Read


Select one of the following three modes in which the Snap executes:

  • 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


Note
For the 'Suggest' in the Order by columns and the Output fields properties, the value of the Table name property should be an actual table name instead of an expression. If it is an expression, it will display an error message "Could not evaluate accessor:  ..." when the 'Suggest' button is pressed. This is because, at the time of "Suggest" button pressed, the input document is not available for the Snap to evaluate the expression in the Table name property. The input document is available to the Snap only during the preview or execution time.


Example

In this basic pipeline, the Teradata Snap selects the records from the table, 'snaplogic"."employee1' with the defined order and the output fields.

The successful execution of the pipeline displays the below output preview:

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Teradata Snap Pack
Teradata Snap Pack
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