In this article

1 Overview
- 1.1 Snap Type
- 1.2 Prerequisites
- 1.3 Support for Ultra Pipelines
- 1.4 Limitations & Known Issues
2 Snap Views
3 Snap Settings
4 Examples
5 Snap Pack History

Overview

You can use this Snap provides functionality to lookup records in the target SQL Server table and returns a selected set of fields for every matched record. The Snap executes one request per multiple input documents to avoid making a request for every input record. JSON paths can be used in the Snap properties and will have values from an incoming document substituted into the properties. 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.

Queries produced by the Snap have the format:

SELECT [Output fields] FROM [Table name] WHERE
[C1 = V11 AND C2 = V21 AND...[Cn = Vn1] OR
[C1 = V12 AND C2 = V22 AND...[Cn = Vn2] OR 
......................................  OR
[Cn = V1n AND Cm = V2m AND...[Cn = Vnm]

The Snap ignores any duplicated lookup condition in the input document stream since it maintains a cache for lookup conditions internally. This Snap supports SQL Server 2008 or newer.

Snap Type

The SQL Server - Lookup Snap is a Read-type Snap that provides functionality to lookup records in the target SQL Server table and return a selected set of fields for every matched record.

Prerequisites

None.

Support for Ultra Pipelines

Works in Ultra Pipelines if PassThrough is enabled. The snap must always produce a document for every input in an Ultra task.

Limitations & Known Issues

None.

Snap Views

Type	Format	Number of Views	Examples of Upstream and Downstream Snaps	Description

Type

Format

Number of Views

Examples of Upstream and Downstream Snaps

Description

Input

Document

Min: 1
Max: 1

JSON Formatter
Mapper

This Snap allows exactly one input view and expects documents in the view. Each document should have values for one AND clause in the WHERE statement.

Each document in the input view should contain a Map data of key-value entries. Input data may contain values needed to evaluate expressions in the Object type, Output fields, and Conditions properties.

If the Pass-though on no lookup match property is unchecked, please make sure input data types match column data types in the database table. Otherwise, you may encounter an error message "Cannot find an input data which is related to the output record .....". If the error view is open, all input data in the batch are routed to the error view with the same error information.

Output

Document

Min: 1
Max: 1

CSV Parser
JSON Parser

This Snap has exactly one output view and produces documents in the view. The output document includes the corresponding input data under the "original" key. If there are no results from the query, each output field will have a null value.

Each document in the output view contains a Map data of key-value entries, where keys are the Output fields property values. The input data that has produced the corresponding output data is also included in the output data under the "original" key.

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 if 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 (): 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 - Lookup Example: Load Employee Tables		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 Example: schema_demo		String/Expression	Specify 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 suggestible and will retrieve available database schemas during suggest values. The values can be passed using the pipeline parameters but not the upstream parameter.
Table name* Default Value: N/A Example: employees_table		String/Expression	Specify the name of the table to execute insert on. The values can be passed using the pipeline parameters but not the upstream parameter.
Output fields	Use this fieldset to enter output fields for SQL SELECT statement.
Output fields	Output fields Default Value: N/A Example: email, address, first, last	String/Expression	Specify the output field names for SQL SELECT statement. If this property is empty, the Snap selects all fields by executing the statement "SELECT * FROM ..."
Lookup conditions*	Use this fieldset to enter or select the lookup column name. The lookup conditions are created by using the lookup column name and the lookup column value. Each row will build a condition, such as lookupColumn1 = $inputField. Each additional row will be concatenated using a logical AND. All rows together build the lookup condition being used to lookup records in the lookup table.
	Value* Default Value: N/A Example: $email, $first, $last	String/Expression	Specify the JSON path of the lookup column value. The value will be provided by the input data field.
	Lookup column name* Default Value: N/A Example: email, first, last	String/Expression	Specify the lookup column name.
Pass-through on no lookup match Default Value: Deselected		Checkbox	Select when there is no lookup matching an input document, the input document will pass through to the output view if this property is checked. Otherwise, it will be written to the error view as an error condition.
Number of Retries Default Value: 0 Example: 3		Integer/Expression	Specify the maximum number of retry attempts when the Snap fails to read. Minimum value: 0
Retry Interval (Seconds) Default Value: 1 Example: 3		Integer/Expression	Specify the minimum number of seconds the Snap must wait before each retry attempt. Minimum value: 1
Option for Unique Identifier Column Default Value: Convert to lower case Example: Convert to upper case		Dropdown list	Conditional. This property 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: Convert to lower case: Modifies the output string to lower case. Convert to upper case: Modifies the output string to upper case.
Snap execution Default Value: Validate & Execute Example: Execute only		Dropdown list	Select 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.

Examples

In this example, we will show how the Lookup Snap retrieves data from a table called 'customer1'.

We can pass the dynamic variable used in the where clause from an upstream Snap like JSON Generator. We try to retrieve customers with the condition applied on 'customername' field. In this example, only two fields ('customername', 'product') are shown in the output fields set in the Output fields property.

The sample output looks like:

SnapLogic Documentation

SQL Server - Lookup