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databases/mongodb/README.md

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+# MongoDB
+
+Simple example of MongoDB usage with Actix Web. For more information on the MongoDB Rust driver,
+visit the [documentation](https://docs.rs/mongodb/2.0.0/mongodb/index.html) and
+[source code](https://github.com/mongodb/mongo-rust-driver).
+
+## Usage
+
+### Install MongoDB
+
+Visit the [MongoDB Download Center](https://www.mongodb.com/try) for instructions on how to use
+MongoDB Atlas or set up MongoDB locally.
+
+### Set an environment variable
+
+The example code creates a client with the URI set by the `MONGODB_URI` environment variable. The
+default URI for a standalone `mongod` running on localhost is "mongodb://localhost:27017". For more
+information on MongoDB URIs, visit the
+[connection string](https://docs.mongodb.com/manual/reference/connection-string/) entry in the
+MongoDB manual.
+
+### Run the example
+
+To execute the example code, run `cargo run` in the `database_interactions/mongodb` directory.