Retrieving Data from MongoDB
Special datalayer elements are used to retrieve data from the MongoDB system and their attributes can be used to form a "query" so that specific data is returned. In some cases, the data retrieved is limited to 16MB.
The available datalayers include the following (click the link for more information and examples):
| Element | Description |
|---|---|
| DataLayer.Mongo Find | Retrieves documents from a MongoDB collection using the MongoDB Find API. |
| DataLayer.Mongo Map Reduce | Runs a MongoDB map-reduce operation to return one or more documents. |
| DataLayer.Mongo Run Command | Runs a MongoDB command, suitable for use with the Aggregation Pipeline, a simpler alternative to using map-reduce operations, to return one or more documents. |
MongoDB results are often hierarchical and may consist of multiple levels of parent-child relationships. In order to work with Logi elements, the data often must be "tabularized" and this can be done by using The Flattener element.
In many respects, these datalayers function exactly as other datalayer elements do and, once retrieved, the data can be filtered and conditioned using all the usual datalayer child elements.