1. Database Operations
1. Create a new database (if the database does not exist, create a database, otherwise switch to the specified database.) ）
Enter use db01
2. Delete the database.
First, use db01 to switch to the database you want to delete.
Enter dbdropdatabase: Deletes the current database.
Second, the collection operation].
1. Create a new collection: dbcreatecollection(collection name).
Enter dbcreatecollection('list01')
Input: show collections or show tables
2. The second way to create a collection: dbThe name of the collection. insert()
In MongoDB, you don't need to create collections. When you insert some documents, MongoDB automatically creates a collection.
Enter dblist02.insert()
3. Delete collection: dbThe name of the collection. drop()
Enter dblist02.drop() deletes the specified collection.
Enter: show collections to view all collections.
4. Collection rename: dbOld collection name. renamecollection("new collection name").
Enter dblist01.renamecollection(“list02”)
Enter: show collections to view all collections.
3. Document Operation] Find documents.
1. Find the document: dbThe name of the collection. find
Unconditionally: dblist02.find() [is equal to viewing all documents in the current collection].
Conditional query: dblist02.find()
2. Query result formatting: dbThe name of the collection. find().pretty()
Formatting: dblist02.find().pretty()
3. Comparison operators (=, <, =, >, =, !=)
Equals (=) is the default equals judgment, with no operator.
Less than ( Find documents with IDs less than 2: db.list02.find(})
Less than or equal to (<=): LTE
Greater than ( >gt
Greater than or equal to (>=): gte
Not equal to (!= )：ne
Query documents with IDs other than 2,4.
4. Range query (in, nin).
Documentation in "[: $in:[ array].
db.list02.find(})
Not in the "[ document: $nin:[ array].
5. Logical operators (and, or).
and : Write multiple conditions in json.
or: Use $or, the value is an array, and each element in the array is JSON
db.list02.find(,]
6. Interval query (limit, skip).
Used to read a specified number of documents: dbThe name of the collection. find().limit (quantity).
db.list02.find().limit(1)
Used to skip a specified number of files: dbThe name of the collection. find().limit (quantity).
db.list02.find().skip(1)
7. Sort: dbThe name of the collection. find().sort()
Parameter 1 is in ascending order.
Parameter -1 is in descending order.
db.con1.find().sort()
8. Fuzzy query: equivalent to %, note no quotation marks.
db.con1.find()
db.con1.find()
Fourth, document operations] added.
Insert document: dbThe name of the collection. insert (document).
db.con.insert([, where both data are inserted.
Fifth, the document operation is deleted.
db.The name of the collection. remove
db.con1.remove()
Sixth, the document operation is updated.
Update Documentation: dbThe name of the collection. update(condition,).
db.con1.update(,}