On the contrary, you can change the schema without having to install a new database with the updated schema. Unlike relational databases, MongoDB does not require you to pre-define the data schema. Mongo is a NoSQL database because it uses a traditional relational structure but JSON-like documents with dynamic schemas. It is a scalable, robust, and reliable platform. MongoDB automatically determines whether to create a multikey index if the indexed field contains an array value you do not need to explicitly specify the multikey type.MongoDB is one of the most demanded NoSQL databases. These multikey indexes allow queries to select documents that contain arrays by matching on element or elements of the arrays. If you index a field that holds an array value, MongoDB creates separate index entries for every element of the array. multikey index: MongoDB uses multikey indexes to index the content stored in arrays.compound index: MongoDB also supports user-defined indexes on multiple fields, i.e.single field: MongoDB supports the creation of user-defined ascending/descending indexes on a single field of a document.You cannot drop this index on the _id field. The _id index prevents clients from inserting two documents with the same value for the _id field.
MongoDB provides a number of different index types to support specific types of data and queries. Hackolade was specially built to support the data types and attributes behavior of MongoDB, including the BSON types. Like JSON, MongoDB's BSON implementation supports embedding objects and arrays within other objects and arrays – MongoDB can even 'reach inside' BSON objects to build indexes and match objects against query expressions on both top-level and nested BSON keys.īSON is a binary serialization format used to store documents and make remote procedure calls in MongoDB. The MongoDB BSON implementation is lightweight, fast and highly traversable. BSON extends the JSON model to provide additional data types, ordered fields, and to be efficient for encoding and decoding within different languages. MongoDB represents JSON documents in binary-encoded format called BSON behind the scenes.
If an inserted document omits the _id field, the MongoDB driver automatically generates an ObjectId for the _id field. In MongoDB, each document stored in a collection requires a unique _id field that acts as a primary key. The data model in the picture below results from the reverse-engineering of the Yelp Challenge Dataset. The application closely follows the terminology of the database. Hackolade was specially built to support the data modeling of MongoDB collections, supporting multiple databases as well. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schemas. MongoDB is a free and open-source cross-platform document-oriented database program. Generate Schema Error during Couchbase reverse-engineering.Document types for Couchbase are not discovered as expected.