SQL Server - Select
In this article
Overview
You can use this Snap to fetch data from an SQL Server database by providing the database and table details. Queries produced by the Snap have the following format:
SELECT [output fields] FROM [table] WHERE [where clause] ORDER BY [ordering] LIMIT [limit] OFFSET [offset]
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.
This Snap supports SQL Server 2008 or higher version.
The sub-millisecond time accuracy for all date/time data types is not supported.
The
Where
clause can only use variables, not constants or pipeline parameters. An example of aWhere
clause is:SALARY =$SALARY
(here we use the SALARY variable of the input document).
Snap Type
SQL Server - Select Snap is a Read-type Snap that executes SQL SELECT statement.
Prerequisites
None.
Support for Ultra Pipelines
Works in Ultra pipelines.
Pipelines fail in the execution mode whenever a value is set in the Limit Offset field.
Limitations & Known Issues
None.
Snap Views
Type | Format | Number of Views | Examples of Upstream and Downstream Snaps | Description |
---|---|---|---|---|
Input | Document |
|
| This Snap allows none or one input view. If the input view is defined, then the where clause can substitute incoming values for a given expression (in such as to use it as a lookup). |
Output | Document |
|
| This Snap has one output view by default and produces one document for each row in the table. 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 SQL Server - Insert or Bulk Load Snap so that the table is created in SQL Server with a similar schema as the source table. This Snap produces the records from the database on its output view, which a downstream Snap can then process. |
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:
Learn more about Error handling in Pipelines. |
Snap Settings
Asterisk (*): Indicates a mandatory field.
Suggestion icon (): Indicates a list that is dynamically populated based on the configuration.
Expression icon (): Indicates whether the value is an expression (if enabled) or a static value (if disabled). Learn more about Using Expressions in SnapLogic.
Add icon (): Indicates that you can add fields in the field set.
Remove icon (): Indicates that you can remove fields from the field set.
Field Name | Field Type | Description | |
Label*
Default Value: SQL Server - Select | String | 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. | |
Schema Name
Default Value: N/A | String/Expression/Suggestion | Specify the database schema name. In case it is not defined, then the suggestion for the Table Name retrieves all tables names of all schemas. The property is suggestible and will retrieve available database schemas during suggest values..
| |
Table Name*
Default Value: N/A | String/Expression/Suggestion | Specify the table to execute the select query on. | |
Where Clause
Default Value: N/A | String/Expression/Suggestion | Specify the WHERE clause of the SELECT statement. This supports document value substitution (such as Examples: Without using expressions
Using expressions
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 | Use this fieldset to specify the columns in the order in which you want to sort the database. The default database sort order will be used. | ||
Column Names
Default Value: N/A | String/Expression | Specify the column names. | |
Limit Offset
Default Value: N/A | Integer/Expression | Specify the offset for the limit clause. This is where the result set should start. Starting row for the query. | |
Limit Rows
Default Value: N/A | Integer/Expression | Specify the number of rows to return from the query. | |
Query Hints
Default Value: N/A | String/Expression | Specify the hints to customize and optimize the database engine in processing the query statement. | |
Output fields | Use this fieldset to specify the output fields for SQL SELECT statement. | ||
Output Field
Default Value: N/A | String/Expression | Specify or select output field names for SQL SELECT statement. To select all fields, leave it at default.
| |
Fetch Output Fields In Schema
Default Value: Deselected | Checkbox | Select this check box to include only the selected fields or columns in the Output Schema (second output view). If you do not provide any Output fields, all the columns are visible in the output.
| |
Pass-through
Default Value: Selected | Checkbox | Select this checkbox to pass the input document through the output view under the key '
| |
Ignore empty result
Default Value: Deselected | Checkbox | Select this checkbox if you do not want to write to the output view when a SELECT operation does not produce any result or is empty. | |
Auto Commit
Default Value: False | 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:
| |
Match data types
Default Value: Deselected | Checkbox | This property applies only when the Output fields property is provided with any field value(s). If this property is selected, the Snap tries to match the output data types same as when the Output fields property is empty (SELECT * FROM ...). The output preview would be in the same format as the one when SELECT * FROM is implied and all the contents of the table are displayed. | |
Number of Retries
Default Value: 0 | Integer/Expression | 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. | |
Retry Interval (seconds)
Default Value: 1 | Integer/Expression | Specify the time interval between two successive retry requests. A retry happens only when the previous attempt resulted in an exception.
| |
Staging mode
Default Value: In memory | Dropdown list | Required when the value in the Number of retries field is greater than 0. Specify the location from the following options to store input documents between retries:
| |
Option for Unique Identifier Column
Default Value: Convert to lower case | Dropdown list | This propery applies only when the Snap returns the unique identifier (GUID) in the output. Specify the unique identifier is stored in the database using an internal format and when it is displayed in the output, it is converted to a string and gets displayed in upper case for HEX characters. Select either of the following options to change the case type. Available options are:
| |
Snap Execution
Default Value: Validate & Execute | Dropdown list | Select one of the following three modes in which the Snap executes:
|
Examples
Fetch employee details from a table in the SQL Server database
This example pipeline demonstrates how to retrieve employee details from the Employee_Demo table.
Configure the Mapper Snap with the Employee name and map it to the target column Emp_Name.
Configure the SQL Server- Select Snap to retrieve the specified employee details (from the "Employee_Demo" table) and Where clause "Emp_Name" = $Emp_Name.
On validation, you can view the employee details in the output preview.
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