https://github.com/mikeckennedy/mongodb-query-helper-for-dotnet

https://github.com/mikeckennedy/mongodb-query-helper-for-dotnet

Last synced: 16 days ago
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• Host: GitHub
• URL: https://github.com/mikeckennedy/mongodb-query-helper-for-dotnet
• Owner: mikeckennedy
• License: mit
• Created: 2014-03-05T23:04:34.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2022-06-28T17:21:01.000Z (over 2 years ago)
• Last Synced: 2024-10-10T19:08:46.912Z (about 1 month ago)
• Language: C#
• Size: 10.1 MB
• Stars: 24
• Watchers: 11
• Forks: 9
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
MongoDB query helper for .NET

===============================

**Available on NuGet**: [https://www.nuget.org/packages/MongoDB.QueryHelper](https://www.nuget.org/packages/MongoDB.QueryHelper)

This library makes working with LINQ to MongoDB queries

easier from C#. Specificially it is for debugging and

runtime inquiry of LINQ queries.

There are two basic use cases:

1. **Explain a LINQ query** (does it use an index for example?)

1. **Convert** a LINQ query to the **JavaScript** code run in MongoDB

Consider this LINQ query:

    var query =

            from p in mongo.People

            where p.Age > 20 && p.Name.Length >= 2

            orderby p.Age descending

            select p;

Calling 

    Console.WriteLine( query.ToMongoQueryText() );

Outputs the following text;

    { "Age" : { "$gt" : 20 }, "Name" : /^.{2,}$/s }

Next, calling explain on query will return a strongly-typed `QueryPlan`

object.

    QueryPlan plan = query.ExplainTyped();

To see the output either work with it's properties, e.g.

    bool usesIndex = plan.CursorType == CursorType.BtreeCursor;

Or just ToString the plan to get:

	{

	  "cursor": "BtreeCursor Age_1 reverse",

	  "isMultiKey": false,

	  "n": 3,

	  "nscanned": 3,

	  "nscannedObjectsAllPlans": 5,

	  "nscannedAllPlans": 5,

	  "nscannedObjects": 3,

	  "scanAndOrder": false,

	  "indexOnly": false,

	  "nYields": 0,

	  "nChunkSkips": 0,

	  "millis": 0,

	  "indexBounds": {

		"Age": [

		  [

			"Infinity",

			20

		  ]

		]

	  },

	  "server": "WIN-7S2IMPQ2TOE:27017",

	  "allPlans": null,

	  "oldPlan": null,

	  "clusteredType": null,

	  "millisShardTotal": 0,

	  "millisShardAvg": 0,

	  "numQueries": 0,

	  "numShards": 0,

	  "filterSet": false,

	  "stats": {

		"type": "FETCH",

		"works": 5,

		"yields": 0,

		"unyields": 0,

		"invalidates": 0,

		"advanced": 3,

		"needTime": false,

		"needFetch": false,

		"isEOF": true,

		"docsTested": 0,

		"children": [

		  {

			"type": "IXSCAN",

			"works": 3,

			"yields": 0,

			"unyields": 0,

			"invalidates": 0,

			"advanced": 3,

			"needTime": false,

			"needFetch": false,

			"isEOF": true,

			"docsTested": 0,

			"children": [],

			"keyPattern": "{ Age: 1 }",

			"boundsVerbose": "field #0['Age']: [1.#INF, 20)",

			"isMultiKey": 0,

			"yieldMovedCursor": 0,

			"dupsTested": 0,

			"dupsDropped": 0,

			"seenInvalidated": 0,

			"matchTested": 0,

			"keysExamined": 3

		  }

		],

		"alreadyHasObj": 0,

		"forcedFetches": 0,

		"matchTested": 3

	  }

	}