It is possible to decode the timestamp from the object id to know exactly when it was generated. ObjectID is a data type provided by the BSON format, uses timestamp, increment value, etc, to create unique ID every time. You can set this key yourself, but if you don’t set the value, MongoDBwill generate it using ObjectID api. In MongoDB, every documents must have a unique _idfield as a primary key. Notice the underscore ID field in this document (row). Here you see an example below of a document (row) stored in MongoDB. Behind the scenes, documents are stored in BSIN (BSON) format which stands for binary JSON.īSON extends the JSON model to provide additional data types, ordered fields, and to be efficient for encoding and decoding within different languages.
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However, this is not always desirable and later we will learn how to impose structure when you want it on MongoDBdocuments.ĭocuments in MongoDB use the JSON format. So documents in the same collection can have completely different structure from each other and that would be OK. MongoDB does not enforce any inherent structure on documents.
The documents themselves are composed of fields, which are like cells in a table.įor example we will be creating a Mongo database with the name of “ nucampsite” The collections contain documents, which is analogous to a row in a table. A MongoDB database contains collections, collections contain documents, documents contain fields.Ī MongoDB database contains collections, a concept that is roughly analogous to the concept of a table. It is designed to be able to handle large amounts of data. MongoDB originated in 2007, the Mongo is short for humongous. We have at least 4 loose classifications of NoSQL databases: Simply meaning that they are not SQL-based relational databases. While SQL databases have been very effective and widespread solutions for managing data, they do have some limitations.Īs time went on increasing demand for new capabilities beyond what SQL-based relational databases can provide has led to a new class of databases, that are loosely grouped as NoSQL category. Some popular Relational Database Management Systems (RDBMS) include MS Access, Oracle, and MySQL. Every row in table must have identical structure, with values for the same columns.
Data is designed to be easy to sort and analyze data, use queries to create new tables with specific criteria, etc.Ī strict schema is enforced on each table. In relational databases, data is represented as tables and columns. SELECT * FROM Partners – This would select all the rows from the Partners tableĬREATE DATABASE campsites – This would create a new database named campsites The SQL syntax itself is relatively simple yet powerful.
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