Instance document formats
A JSON instance document for a MongoDB collection can represent a single document in a collection or many documents in a collection. The MongoDB adapter supports both formats.
Single document format
{
JSON-document-data
}
For
example:{
Customer : Company X,
Location : Europe
}
Multiple document format
[
{
JSON-document-data
},
{
JSON-document-data
}
]
For
example:[
{
Customer : Company X,
Location : Europe
},
{
Customer : Company Y,
Location : North America
}
]
Managing document formats
When the schema of an input card represents single instance document, the -SDF command is required. The -SDF command indicates that the adapter is to send a non-array style, single JSON instance document to the map, even if the adapter fetches multiple documents. A single-document schema cannot validate an array-style, multiple-document instance.
When the schema of an output card represents single instance document, the -SDF command is required to ensure the adapter treats the instance as single document; otherwise, adapter errors occur when inserting documents into the MongoDB collection.
When you specify the -SDF command, the MongoDB adapter cannot transmit documents in array-style, multiple-document format.
By default, the MongoDB adapter processes instance documents as multiple-document arrays (multiple-document format). There is no corresponding command option.
When the schema of an input card represents an array-style (multiple-document) instance document, the Native JSON parser can successfully process documents that are in either single-document format or multiple-document format. When the schema of an output document represents an array-style instance document, the adapter can insert only documents that are in multiple-document format into a MongoDB collection.