MongoDB: Mastering the shell
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The document discusses using the MongoDB shell for debugging queries, testing, and administration. It notes some limitations of using JavaScript in the shell, like number and date handling. It then demonstrates various shell commands like insert, find, runCommand, and profiling. Finally it discusses additional shell features like loading scripts, exposing functions, and printing indexes.
![Cool functionsprintjson -> tojsonforEach on array/query/cursor> [{x:1},{y:1}].forEach(function(x){printjson(x)}){ "x" : 1 }{ "y" : 1 }Object.bsonsizeObject.bsonsize(c.findOne({name:”scott”}))load(file)run(file)](https://image.slidesharecdn.com/mongosf-masteringtheshell-110626114039-phpapp02/85/MongoDB-Mastering-the-shell-14-320.jpg)
![Print all Indexesdb.getCollectionNames().forEach(function(x){ print(“Collection: “ + x);printjson(db[x].getIndexes());})](https://image.slidesharecdn.com/mongosf-masteringtheshell-110626114039-phpapp02/85/MongoDB-Mastering-the-shell-15-320.jpg)
MongoDB: Mastering the shell
- 1. Hacking the Shell Raw MongoDB (as you like it)Scott Hernandez – scott@10gen
- 2. What is the shell?
- 3. What is it good for?Debugging Queries/SyntaxTestingAdministrationScripting GlueNot for building apps, probably
- 4. The Bad: JS TypesNumbers Suck (but getting better)32/64bit signed (int/long) – 1.5.4>NumberLong(“”)Displayed funny in early versionsEverything is a 64bit fp (double)Dates are a challengenew Date(“1/1/1”)new ISODate(…)Not Date(“1/1/1”) -> string
- 5. The Bad: JS is SlowShellAlways Safe/GLELoops and updatesData conversionsServerIt pretty much applies here tooBe careful with numbers as well
- 6. Insert, Save, Update, RemoveDemo now for(i = 0; i <1000; i++) { db.test.insert({x:i, ts: new Date()}) }
- 7. Command Line--evalit/cursorPrinting valuesPass in a script
- 8. Loading ScriptsCommand lineload() – also runs
- 11. ProfilingsetProfilingLevel(lvl, <ms>)0: none1: time-based2: allgetProfilingLevel()Reading from profile collection>db.system.profile.find()
- 12. Help> help> help admin> help misc> db.help()> db.coll.help()
- 13. Expose FunctionsLeave off the () to see the function:> db.getSisterDBfunction (name) { return this.getMongo().getDB(name);
- 14. Cool functionsprintjson -> tojsonforEach on array/query/cursor> [{x:1},{y:1}].forEach(function(x){printjson(x)}){ "x" : 1 }{ "y" : 1 }Object.bsonsizeObject.bsonsize(c.findOne({name:”scott”}))load(file)run(file)
- 15. Print all Indexesdb.getCollectionNames().forEach(function(x){ print(“Collection: “ + x);printjson(db[x].getIndexes());})
- 16. Getting the Biggest Docvar cursor = db.coll.find();var biggest=0;var doc = {};cursor.forEach(function (x) { var size = Object.bsonsize(x); if (size > biggest) { biggest=size; doc = x; }});
- 17. Cursors: it“it” global varfind automatically sets it
- 19. DBRefHas fetch()Easy to create