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Import Filtered Data fromMongoDB

This example shows how to import flight data from a MongoDB®collection into the MATLAB®workspace using the Database Toolbox™ interface for MongoDB. The example then shows how to use a MongoDB query with filter criteria and a field list, and how to perform a simple data analysis based on the filtered flight data.

To run this example, you must first install the Database Toolbox interface for MongoDB. For details, seeDatabase Toolbox Interface for MongoDB Installation.

Create a MongoDB connection to the databasemongotest. Here, the database serverdbtb01hosts this database using port number27017.

server ="dbtb01"; port = 27017; dbname ="mongotest"; conn = mongo(server,port,dbname)
conn = mongo with properties: Database: 'mongotest' UserName: '' Server: {'dbtb01'} Port: 27017 CollectionNames: {'airlinesmall', 'employee', 'largedata' ... and 3 more} TotalDocuments: 23485919

connis themongoobject that contains the MongoDB connection. The object properties contain information about the connection and the database.

  • The database name ismongotest.

  • The user name is blank.

  • The database server isdbtb01.

  • The port number is27017.

  • This database contains six document collections. The first three collection names areairlinesmall,employee, andlargedata.

  • This database contains 23,485,919 documents.

Verify the MongoDB connection.

isopen(conn)
ans = logical 1

The database connection is successful because theisopenfunction returns1. Otherwise, the database connection is closed.

Specify theairlinesmallcollection. Define the MongoDB query to filter the flight data for the years 1998 through 1999. Specify fields to retrieve from the collection.

collection ="airlinesmall"; mongoquery ='{"Year":{$gte:1998,$lt:2000}}'; fields = ['{"Year":1.0,"Month":1.0,"DayofMonth":1.0,"DayOfWeek":1.0,'...'"DepTime":1.0,"ArrTime":1.0}'];

Retrieve flight data using the MongoDB connection.documentsis a structure array with fields that correspond to the specified fields.

documents = find(conn,collection,'Query',mongoquery,'Projection',fields)
documents = 10911×1 struct array with fields: x_id Year Month DayofMonth DayOfWeek DepTime ArrTime

Determine the unique years in the data.

years = [documents(:).Year]; unique(years)
ans = 1998 1999

Close the MongoDB connection.

close(conn)

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