Mongodb addition, deletion, modification and search

(1) increase:

Db.collname.insert ({name: "user1", age: "20"}) add a piece of regular data

The added numbers are key-value pairs in json format, and the subsequent values need to be in double quotation marks or quotation marks

Db.collname.insert ({time:new Date ()}) mongodb supports js, and you can add js statements to query

Db.collname.insert ({name: ["user1", "user2", "user3"]}); add an array of data

Db.collname.insert ({name: {first: "user1", middle: "user2", last: "user3"}}) add a piece of data with an embedded document, (a row of data in mongodb is also known as a document)

Custom document insertion:

> doc= {

... Name: "user"

... Age: "20"

... Sexy: "man"

...}

{"name": "user", "age": "20", "sexy": "man"}

> db.c1.insert (doc)

(2) check

View all the data of collection (C1)

Db.c1.find ()

View the data with the user name smith

Db.c1.find (name: "smith")

View all data except the age field

Db.c1.find ({}, {age:0})

Check that the user name is smith, excluding other fields in the age field.

Db.c1.find ({name: "smith"}, {age:0})

Only view the age field whose user name is smith

Db.c1.find ({name: "smith"}, {age:1})

View data over the age of 20

Db.c1.find ({age: {$gt:20}})

View data under the age of 20

Db.c1.find ({age: {$lt:20}})

View data older than or equal to 20

Db.c1.find ({age: {$gte:20}})

View data whose age is less than or equal to 20

Db.c1.find ({age: {$lte:20}})

View data that are not equal to 20 years old

Db.c1.find ({age: {$ne:20}})

View data with both singging and football hobbies

Db.c1.find ({hobby: {$all: ["singging", "football"]}}); ($all must include all, and $in needs to include only one of them)

Check data with singging or football hobbies.

Db.c1.find ({hobby: {$in: ["singging", "football"]}})

Check the data without singging or football hobbies.

Db.c1.find ({hobby: {$nin: ["singging", "football"]}})

View the data where a field exists: output only five pieces of data

Db.c1.find ({name: {$exists:true}}) .limit (5)

Take a model to view the data with a Mantissa of age

Db.c1.find ({age: {$mod: [10Jing 1]}})

View data that meet at least one requirement $or

Db.c1.find ({$or: [{age:20}, {sexy: "man"})

View a data that does not meet the requirements $nor

Db.c1.find ({$nor: [{age:20}, {sexy: "man"})

View data with an array length equal to 3 (set an as an array)

Db.c1.find ({a: {$size:3}})

Retrieve all users whose name attribute begins with u and ends with 4 (regular expressions can be used)

Db.c1.find ({name:/u.*4 $/ I})

Sort / / 1 for ascending order,-1 for descending order

Db.c1.find () .sort ({_ id: 1})

Check the unique value.

Db.c1.distinct ("age")

Paging query:

Db.c1.find () .skip (20) .limit (8)

Or: db.c1.find ({}, {}, 8pm 20)

Number of query records:

Db.c1.find () .count ()

Query a document that does not have a value or does not exist:

Db.c1.find (name:null)

The usage of $slice in query

Db.posts.find ({}, {comments: {$slice: 5}}) / / the first five comments

Db.posts.find ({}, {comments: {$slice:-5}}) / / the last 5 comments

Db.posts.find ({}, {comments: {$slice: [20,10]}) / / skip 20, limit 10

Db.posts.find ({}, {comments: {$slice: [- 20,10]}) / / 20 from end, limit 10

(3) deletion

Delete all data under C1 (collection)

Db.c1.remove ()

Delete data with an id of 10

Db.c1.remove ({_ id:10})

Suggestion: when deleting an operation, try to use _ id as a condition.

In some cases, when you perform a remove operation on a record, there may be a update operation on the record, so the record may not be deleted. If you think this is not satisfactory, you can add $atomic: db.videos.remove ({rating: {$lt: 3}, $atomic: true}) to the remove operation.

(4) Reform

Syntax db.collection.update (criteria, objNew, upsert, multi)

Criteria: the object used to set query criteria

Objnew: the object used to set the update content

Upsert: if the record already exists, update it, otherwise add a new record

Multi: if there are multiple eligible records, update them all

Note: by default, only the first eligible record is updated

If there is an update, if it does not exist, add a record db.mycollection.save (x)

Change the age whose id is 0 to 20

Db.user.update ({_ id:0}, {$set: {age:20}})

Add 20 to the age with id 0

Db.user.update ({_ id:0}, {$inc: {age:20}})

Subtract 20 from the age with an id of 0

Db.user.update ({_ id:0}, {$inc: {age:-20}})

Delete the sex field whose id is 0

Db.user.update ({_ id:0}, {$unset: {sex:1}})

Modify the hobby field whose id is 0 (provided that hobby is an array or does not exist, otherwise an error will be reported)

Db.user.update ({_ id:0}, {$push: {hobby:'football'}})

{$pushAll: {field: value_array}} uses the same as above

Add a data to the hobby field where id is 0 (provided hobby is an array or does not exist, otherwise an error will be reported)

Db.user.update ({_ id:0}, {$addToSet: {hobby:'football'}})

Delete the last data in the hobby field whose id is 0 (provided that hobby is an array or does not exist, otherwise an error will be reported

Db.user.update ({_ id:0}, {$pop: {hobby:'football'}})

Delete the eligible data in the hobby field whose id is 0 (provided that hobby is an array or does not exist, otherwise an error will be reported

Db.user.update ({_ id:0}, {$pull: {aihao:'bike'}})

Change the name of the name field in the data with id 0 to username

Db.user.update ({_ id:0}, {$rename: {'name':'username'}})