In this article

Overview

You can use the Azure SQL - Execute Snap to execute single simple DML (SELECT, INSERT, UPDATE, DELETE) type statements.

note
  • This Snap works only with single queries.

  • For the comprehensive scripting functionality offered by the various databases, we recommend you to use the stored procedure functionality offered by their chosen database in the Stored Procedure Snap.

  • This Snap works only with single queries.

  • For the comprehensive scripting functionality offered by the various databases, we recommend you to use the stored procedure functionality offered by their chosen database in the Stored Procedure Snap.

Snap Type

The Azure SQL Execute Snap is a WRITE-type Snap that writes the results of the executed SQL queries.

Prerequisites

Support for Ultra Pipelines

Works in Ultra Pipelines.

Supported Versions

This Snap supports SQL Server 2008 or higher version.

Limitations

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

Known Issues

None.

Behavior Change

  • In 4.26, when the stored procedures were called using the Database Execute Snaps, the queries were treated as write queries instead of read queries. So the output displayed message and status keys after executing the stored procedure.
    In 4.27, all the Database Execute Snaps run stored procedures correctly, that is, the queries are treated as read queries. The output now displays message key, and OUT params of the procedure (if any). The status key is not displayed.

  • If the stored procedure has no OUT parameters then only the message key is displayed with value success.

If you have any existing Pipelines that are mapped with status key or previous description then those Pipelines will fail. So, you might need to revisit your Pipeline design.

Snap Views

Type

Format

Number of Views

Examples of Upstream and Downstream Snaps

Description

Input 

Document

  • Min: 0

  • Max: 1

  • Mapper

  • Copy

  • JSON Generator

  • The dynamic variables used in the execute query can be defined by providing values upstream.

  • If the input view is defined, then the where clause substitutes incoming values for a specific query.

Output

Document

 

  • Min: 0

  • Max: 1

  • JSON Formatter

  • Any document processing Snap can be used downstream.

  • The Snap produces documents in the output 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.

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:

  • Stop Pipeline Execution: Stops the current Pipeline execution when the Snap encounters an error.

  • 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

  • Asterisk ( * ): Indicates a mandatory field.

  • Suggestion icon ((blue star)): Indicates a list that is dynamically populated based on the configuration.

  • Expression icon ((blue star) ): Indicates the value is an expression (if enabled) or a static value (if disabled). Learn more about Using Expressions in SnapLogic.

  • Add icon ( (blue star) ): Indicates that you can add fields in the field set.

  • Remove icon ( (blue star)): Indicates that you can remove fields from the field set.

Field

Field Type

Description

Label

Default Value: Azure SQL - Execute
Example: Azure SQL - Execute

String

Specify a unique name for the Snap.

SQL statement*

Default Value: N/A
Example: select * from “dob”, “Persons”

String/Expression

Specifiy the SQL statement to execute on the server. There are two possible scenarios that you encounter when working with SQL statements in SnapLogic. 

Learn more about scenarios to execute your SQL statements.

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

  • 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. 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.

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

  • 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. 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.

  • Be cautious when running your queries, because you can drop your database and lock tables while executing SQL statements.

  • When trying to access a column name that contains specific characters supported by Azure SQL, such as $, #, @, such field names should be enclosed in square brackets.

Query type

Default Value: Auto
Example: Read

Dropdown list/Expression

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.

Pass through

Default Value: Selected

Checkbox

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.

Ignore empty result


Default value: Deselected

Checkbox

Select this checkbox if you want the Snap to ignore empty fields and not write any document to the output view when a SELECT operation does not produce any result. If this property is not selected and the Pass through property is selected, the input document will be passed through to the output view.

Number of Retries

Default Value: 0
Example: 3

Integer/Expression

Specify the maximum number of retry attempts the Snap must make in case there is a network failure, and the Snap is unable to read the target file. The request is terminated if the attempts do not result in a response.

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.

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.

Retry Interval (Seconds)

Default Value: 1
Example: 10

Integer/Expression

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

Auto commit

Default Value: Use account setting
Example: True

Dropdown list

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: TrueFalse, 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.

note

'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.

'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.

Snap Execution

Dropdown list


Additional Information

Scenarios to successfully execute your SQL statements

Scenario 1: Executing SQL statements without expressions.

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.

  • "EMPNO=$EMPNO and ENAME=$EMPNAME"

  • "emp='" + $emp + "'"

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

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

Examples:

  • 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.

Single quotes in values must be escaped

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 value

Use

Has no single quotes

Schaum Series

'Schaum Series'

Contains single quotes

O'Reilly's Publication

'O''Reilly''s Publication'


Examples

Azure SQL - Execute Snap as a Standalone Pipeline

The following pipeline describes how the Snap functions as a standalone Snap in a pipeline:

 

Typical Snap Configurations

The key configuration of the Azure SQL - Execute lies in how you pass the SQL statement to read Azure records. As it applies in SnapLogic, you can pass SQL statements in the following manner:

Without Expression: Directly passing the required SQL statement in the Azure SQL Execute Snap.

Extract, Transform, Load

The following example use case demonstrates a broader business logic involving the ETL transformations, that shows how typically in an enterprise environment, an execute functionality is used. This pipeline reads and moves files from the SQL Server Database to the Azure SQL Database and the Azure SQL Execute Snap reads the newly loaded table on the Azure SQL instance.

  1. Extract: The SQL Server Select Snap reads the data from the SQL Server Database.

  2. Load: The Azure SQL Execute Snap inserts the data into an Azure SQL table.

  3. Read: Another Execute Snap is used to read the data from the newly loaded table on the Azure SQL database.


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