The SYS_INDEXES table lists the indexes of the collections as MongoDB has them, including the index of _id, and their options. Views have no indexes. It has the following columns:

Column Name	Data Type	Description
TABLE_CATALOG	VARCHAR	The name of the database of the connection.
TABLE_SCHEMA	VARCHAR	Not used in dotConnect for MongoDB. Always NULL.
TABLE_NAME	VARCHAR	The name of the collection which the index belongs to.
INDEX_NAME	VARCHAR	The name of the index. The index of _id is named _id_.
IS_PRIMARY	BOOLEAN	Indicates whether the index is the primary key. True for _id_ only.
IS_UNIQUE	BOOLEAN	Indicates whether the index is unique. True for _id_ and for an index created with the unique option.
IS_SPARSE	BOOLEAN	Indicates whether the index is sparse: it skips the documents that do not have the indexed field.
IS_PARTIAL	BOOLEAN	Indicates whether the index is partial: it covers only the documents that match its filter.
FILTER	VARCHAR	The filter of a partial index (partialFilterExpression) as JSON, for example {"email":{"$exists":true}}. NULL for other indexes.
EXPIRE_AFTER_SECONDS	BIGINT	The lifetime of the documents in seconds for a TTL index (expireAfterSeconds). NULL for other indexes.
DEFINITION	VARCHAR	The whole description of the index in MongoDB as JSON, for example {"v":2,"key":{"name":1},"name":"ix_name","unique":true}.