Azure SQL - Execute

Overview

The Azure SQL - Execute Snap executes 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 use the stored procedure functionality offered by their chosen database in the Stored Procedure Snap.



Supported Accounts

Prerequisites

  • Valid Azure SQL Account.
  • Access to Azure SQL and the required permissions to execute T-SQL queries.

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.

Behavior changes

  • 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.
Note: 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 Description Examples of upstream and downstream Snaps
Input

This Snap has at most one document input view.

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

This Snap has at most one document output view.

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.
Learn more about Error handling.

Examples

Snap settings

Note: Learn about the common controls in the Snap settings dialog.
Field/Field set 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: Azure SQL - Execute

Example: Azure SQL - Execute
SQL statement*

String/Expression		 Required. Specify the SQL statement to execute on the server. When working with SQL statements in SnapLogic, you may encounter two possible scenarios. Learn more about scenarios to execute your SQL statements.
Note:
  • We recommend you add a single query in the SQL Statement field.
  • Valid JSON paths defined in the WHERE clause for queries/statements will be substituted with values from an incoming document. If a document is missing a value to be substituted into the query/statement, it will be written to the error view.
  • 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.
CAUTION:
  • 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.

Default value: N/A

Example: select * from "dob", "Persons"
Query type

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.

Default value: Auto

Example: Read
Pass through

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.

Default value: Selected
Ignore empty result

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.

Default value: Deselected
Number of Retries

Integer/Expression		 Specify the maximum number of retry attempts the Snap must make in case of network failure.

When you set the Number of retries to more than 0, the Snap generates duplicate records when the connection is not established. To prevent duplicate records, we recommend that you follow one of the following:

  • Set the Number of retries to 0 (default value) to prevent duplicate records from being passed downstream while executing a pipeline.
  • Use a Primary key to prevent records from being inserted into the database.
  • Use an Upsert instead of an Insert statement.

Default value: 0

Example: 3
Retry Interval (Seconds)

Integer/Expression		 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
Auto commit

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: 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.
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.

Important: DDL queries used in the Database Execute Snap will be committed by the Database itself, regardless of the Auto-commit setting. When Auto commit is set to false for the DML queries, the commit is called at the end of the Snap's execution. The Auto commit needs to be true in a scenario where the downstream Snap does depend on the data processed on an Upstream Database Execute Snap containing a DML query. When the Auto commit is set to the Use account setting on the Snap, the account level commit needs to be enabled.

Default value: Use account setting

Example: True
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.

Additional information

Scenarios to successfully execute your SQL statements

Scenario 1: Executing SQL statements without expressions.

  • The SQL statement must not be within quotes.
  • The $<variable_name> parts of the SQL statement are expressions. In the 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.

  • 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 example, $tablename.
  • The $<variable_name> parts of the SQL statement are bind parameter, and must be within quotes. In the example, $id and $book.

Examples:

  • "EMPNO=$EMPNO and ENAME=$EMPNAME"
  • "emp='" + $emp + "'"
  • "EMPNO=" + $EMPNO + " and ENAME='" + $EMPNAME+ "'"
Note: Table name and column names must not be provided as bind parameters. Only values can be provided as bind parameters.
Note:
  • The non-expression form uses bind parameters, so it is much faster than executing N arbitrary SQL expressions.
  • Using expressions that join strings together to create SQL queries or conditions has a potential SQL injection risk and hence unsafe. Ensure that you understand all implications and risks involved before using concatenation of strings with '=' Expression enabled.
  • The '$' 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'