The document shows examples of queries that can be performed on a MongoDB collection, including finding documents by field values, regular expressions, and querying embedded documents, as well as update operations like setting values, incrementing values, pulling from arrays, and adding to arrays. It also provides examples of MapReduce operations in MongoDB and using finalize functions.

9. {
"_id" : ObjectId("4dcd3ebc9278000000005158"),
"timestamp" : ISODate("2011-05-13T14:22:46.777Z"),
"binary" : BinData(0,""),
"string" : "abc",
"number" : 3,
"subobj" : {"subA": 1, "subB": 2 },
"array" : [1, 2, 3],
"dbref" : [_id1, _id2, _id3]
padding
}

10. { db.coll.find({"string": "abc"});
db.coll.find({ "string" : /^a.*$/i });
"_id" : ObjectId("4dcd3ebc9278000000005158"),
"timestamp" : ISODate("2011-05-13T14:22:46.777Z"),
db.coll.find({"subobj.subA": 1});
db.coll.find({"subobj.subB": {$exists: true} });
"binary" : BinData(0,""),
"string" : "abc", db.coll.find({"number": 3});
db.coll.find({"number": {$gt: 1}});
"number" : 3,
"subobj" : {"subA": 1, "subB": 2 },
"array" : [1, 2, 3],
db.coll.find({"array": {$all:[1, 2]} });
"dbref" : [_id1, _id2, _id3]
db.coll.find({"array": {$in:[2, 4, 6]} });
padding
}

11. {
"_id" : ObjectId("4dcd3ebc9278000000005158"),
"timestamp" : ISODate("2011-05-13T14:22:46.777Z"),
{ $set : {"string": "def"} }
"binary" : BinData(0,""), { $inc : {"number": 1} }
"string" : "def",
{ $pull : {"subobj": {"subB": 2 } } }
"number" : 4,
"subobj" : {"subA": 1, "subB": 2 },
"array" : [1, 2, 3, 4, 5, 6],
"dbref"$addToSet : { "array" : { $each : [ 4 , 5 , 6 ] } } }
{ : [_id1, _id2, _id3]
"newkey" : "In-place"
} { $set : {"newkey": "In-place"} }

14. Member1 Member2
Primary Secondary
Member4 Member3
Secondary Secondary

15. Member1 Member2
Primary Secondary
Member4 Member3
Secondary Secondary

16. Member1 Member2
Primary Secondary
Member4 Member3
Secondary Secondary

17. Member2
Secondary
Member4 Member3
Secondary Secondary

18. Member1
Primary
Member6 Member2
Secondary Secondary
Member5 Member3
Secondary Secondary
Member4
Secondary

19. Member1
Primary
Member6 Member2
Secondary Secondary
Member5 Member3
Secondary Secondary
Member4
Secondary

20. Member1
Primary
Member6 Member2
Secondary Secondary
Member5 Member3
Secondary Secondary
Member4
Secondary

24. Chunk
Shard Key Chunk
200MB

25. Cluster
Shard Servers (Data)
config Servers
(Shard Configration) shard1 shard2 shard3
[ a, f ) [ k, n) [ o, t ) Chunk
[ f, k ) [ n, o ) [ t, } )
mongos Servers (Routers)

26. http://www.mongodb.org/display/DOCS/Introduction

27. primary
Shard
primary
1
( mongos
primary primary primary
)
Shard
cinfig Shard
mongos
http://www.mongodb.org/display/DOCS/Introduction

28. shard1 shard2
[ a, f ) [ n, o ) [ o, t)
[ 0, 9)
[ f, k ) [ k, n)
shard1 shard2
[ a, f ) [ o, t) [ n, o )
[ f, k ) [ k, n) [ 0, 9)

34. m = function(){
this.tags.forEach{
function(z) {
emit(z, {count: 1});
}
};
};
r = function(key, values) {
var total=0;
for (i=0, i<values.length, i++)
total += values[i].count;
return { count : total };
}
res=db.things.mapReduce(m,!r);
# finalize