The basic crud for MongoDB learning notes

Mongo command:

• Show Databases/dbs;
• Use test;
• Show Tables/collections;
• Db.help ()
• Db.createcollection (' user ')
• Db.user.insert ({name: ' Sky ', age:22})
• Db.user.insert ({_id:2, Name: ' Allen ', age:23})
• Db.user.find ()
• Db.user.drop ();
• Db.dropdatabase ();
• Db.stu.remove ({sn: ' 001 '})
• Db.stu.remove ({sn: ' 001 '}, True) #第二个属性表示只影响一行
• Db.stu.update ({name: ' Liubei '},{name: ' Guanyu ', age:20}) # The update in MONGO is a new document that replaces the old document directly, not the modification. If you change only one field, you need to use the set
• Db.stu.update ({name: ' Guanyu '},{$set: {name: ' Sky '}})

Update Specific actions:

• $set Modify the value of a column
• $unset Delete a column
• $rename Rename a column
• $inc Grow a column

Db.stu.update ({name: ' Wukong '},{$set: {name: ' DZSF '}, $unset: {jingu:1}, $rename: {sex: ' Gendar '}, $inc: {age:1}}) #默认u Pdate only 1 lines.

Db.stu.update ({name: ' Wukong '},{$set: {name: ' DZSF '}, $unset: {jingu:1}, $rename: {sex: ' Gendar '}, $inc: {age:1}},{m Ulti:true})

#如果有这条记录就更新, if not, insert

Db.stu.update ({name: ' Bill '},{$set: {name: ' Bill ', Sex: ' M ', age:500}},{upsert:true})

#但是如果我要插入的字段不止这些, when inserting, you need to add more fields, using Setoninsert.

Db.stu.update ({name: ' Kevin '},{$set: {name: ' Bill ', Sex: ' M ', age:500}, $setOnInsert: {address: ' Shanghai '}},{upsert: True})

#第一部分查询表达式, the second part queries the column.

Db.stu.find ({},{name:1})

#id属性默认查出, if you don't want

Db.stu.find ({},{name:1, _id:0})

The basic crud for MongoDB learning notes