SQL Server - Lookup

Snap type:

Read

Description:

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.

Expected upstream Snaps: Any Snap which produces documents in the output view, such as CSV Parser, JSON Parser, Structure, Mapper.

Expected downstream Snaps: Any Snap which receives documents in the input view, such as JSON Formatter, Structure, Mapper. The CSV Formatter will cause an error since the output data is not a flattened Map data.

Expected input: 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.

Expected output: 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.

Prerequisites:

None

Support and limitations:

Ultra pipelines: May work in Ultra Pipelines.
Spark mode: Not supported in Spark mode.

Account:

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

Views:

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

Settings

Label

Required.

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

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.

Example: dbo
Default value: [None]

Table Name
Required.

The name of the table to execute insert on.
Example: dbo.people

Default value: [None]

Output fields
Required.

Enter or select output field names for SQL SELECT statement. If this property is empty, the Snap selects all fields by executing the statement "SELECT * FROM ..."
Example: email, address, first, last
Default: [None]

Lookup conditions

Required.

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.

Default value: [None]

Value

Required.

Enter or select the JSON path of the lookup column value. The value will be provided by the input data field.
Example: $email, $first, $last
Default value: [None]

Lookup column name

Required.

Enter or select the lookup column name.
Example: email, first, last
Default value: [None]

Pass-through on no lookup match

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.

Default value: Not selected

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:

Snap History

4.5.0

Resolved an issue in SQL Server Lookup Snap that occurred when handling case-insensitive field values.

January 2014

Initial release of this Snap.