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Snap type

Write


Description

This Snap allows you to execute arbitrary SQL.

This Snap works only with single queries.


You can drop your database with it, so be careful.

Valid JSON paths that are defined in the where clause for queries/statements will be substituted with values from an incoming document. Documents will be written to the error view if the document is missing a value to be substituted into the query/statement. 

If a SELECT query is executed, the query's results are merged into the incoming document and any existing keys will have their values overwritten. On the other hand, the original document is written if there are no results from the query.


Expected upstream Snaps:  The dynamic variables used in the execute query can be defined by providing values upstream. The document generator Snaps like JSON Generator can be used in upstream.
Expected downstream Snaps: The Snap will output one document for every record retrieved, hence any document processing Snap can be used downstream.

The SAP HANA Execute Snap is for simple DML (SELECT, INSERT, UPDATE, DELETE) type statements. For the comprehensive scripting functionality offered by the various databases, users should use stored procedure functionality offered by their chosen database in the Stored Procedure Snap.


Prerequisites

[None]


Support and limitations

Works in Ultra Task Pipelines.

Behavior Change

Account

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


Views


InputThis Snap has at most one document input view. If the input view is defined, then the where clause can substitute incoming values for a given expression.
OutputThis Snap has at most one document output view. If an output view is available and an update/insert/merge/delete statement was executed, then the original document that was used to create the statement will be output with the status of the statement executed.
Error

This Snap has at most one document error view and produces zero or more documents in the view.

Database write Snaps output all records of a batch (as configured in your account settings) to the error view if the write fails during batch processing.



Settings

Label*


Specify 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.

SQL statement
Required*


Specify the SQL statement to execute on the server. 

Scenario 1: Executing SQL statements without expressions

If the expression toggle of the SQL statement field is not selected:  

  • The SQL statement must not be within quotes. 
  • The $<variable_name> parts of the SQL statement are expressions. In the below example, $id and $book.

Examples:

Additionally, the JSON path is allowed only in the WHERE clause. If the SQL statement starts with SELECT (case-insensitive), the Snap regards it as a select-type query and executes once per input document. If not, it regards it as write-type query and executes in batch mode.

Scenario 2: Executing SQL queries with expressions 

If the expression toggle of the SQL statement field is selected: 

  • The SQL statement must be within quotes. 
  • The + $<variable_name> + parts of the SQL statement are expressions, and must not be within quotes. In the below example, $tablename.
  • The $<variable_name> parts of the SQL statement are bind parameter, and must be within quotes. In the below example, $id and $book.



 Table name and column names must not be provided as bind parameters. Only values can be provided as bind parameters.


Examples:


We recommend you to add a single query in the SQL Statement field.


When the SQL statement property is an expression, the pipeline parameters are shown in the suggest, but not the input schema.


  • The non-expression form uses bind parameters, so it is much faster than executing N arbitrary SQL expressions. 
  • Using expressions that join strings together to create SQL queries or conditions has a potential SQL injection risk and hence unsafe. Ensure that you understand all implications and risks involved before using concatenation of strings with '=' Expression enabled.
  • The '$' sign and identifier characters, such as double quotes (“), single quotes ('), or back quotes (`), are reserved characters and should not be used in comments or for purposes other than their originally intended purpose.


Any relational database (RDBMS) treats single quotes (') as special symbols. So, single quotes in the data or values passed through a DML query may cause the Snap to fail when the query is executed. Ensure that you pass two consecutive single quotes in place of one within these values to escape the single quote through these queries.

For example:

If String To pass this valueUse
Has no single quotes
Schaum Series
'Schaum Series'
Contains single quotes
O'Reilly's Publication
'O''Reilly''s Publication'


Default Value: [None]

Query type

Select the type of query for your SQL statement (Read or Write).

When Auto is selected, the Snap tries to determine the query type automatically.
If the execution result of the query is not as expected, you can change the query type to Read or Write.

Default Value: Auto
Example: Read

Pass through


Select this checkbox to pass the input document to the output view under the key 'original'. This property applies only to the Execute Snaps with SELECT statement.

Default Value: Selected


Ignore empty result


Select this checkbox to ignore empty result; no document will be written to the output view when a SELECT operation does not produce any result.
If you deselect this checkbox and select the Pass through checkbox, the input document will be passed through to the output view.

Default Value: Not selected


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

'Auto commit' may be enabled for certain use cases if PostgreSQL jdbc driver is used in either Redshift, PostgreSQL or generic JDBC Snap. But the JDBC driver may cause out of memory issues when Select statements are executed. In those cases, “Auto commit" in Snap property should be set to ‘False’ and the Fetch size in the “Account setting" can be increased for optimal performance.

Number of retries

Specify the maximum number of attempts to be made to receive a response. The request is terminated if the attempts do not result in a response.

Default Value: 0
Example: 3

Ensure that the local drive has sufficient free disk space to store the temporary local file.


Retry interval (seconds)

Specify the time interval between two successive retry requests. A retry happens only when the previous attempt resulted in an exception. 

Default Value: 1
Example: 10


Examples

In this example, we have a table named USER that stores user details. It has 3 columns: NAME, AGE and CITY. We will execute the query and retrieve users with age 60 with this pipeline. 

 

We need to provide the query used to pull the data from USER table in SQL statement property. We will provide dynamic variable values from upstream Snap JSON Generator.

Sample output looks like below: