1. MongoDB install pit:

  2. Mongo use:

    1. PS: A collection in MongoDB is a table, and a document is a piece of data

    2. Select and create a database syntax format: use database name

    3. Syntax format for inserting documents: db. collection name.

    4. Find (); db.set noun.find ();

    5. FindOne ({userID :’1013′}); findOne({userID :’1013′});

    6. Find ([optional condition]). Limit (Number of returned data items);

    7. Modify the syntax format of the document: db. collection name. update(condition, modified data)

      1. Db.spit. update({_id:”1″},{visits:NumberInt(1000)});
      2. Db.spi. update({_id:”2″},{$set:{visits:NumberInt(2000)}});

    8. Delete document: db. collection name. Remove (condition);

    9. Db. Collection name. Remove ({});

    10. Count (); db. set name. count();

    11. Count ({[optional condition]}); count({[optional condition]}); count({[optional condition]});

    12. Fuzzy query: / Fuzzy query string /

      1. Db.spi. find({content:/ traffic /})
      2. Db.spi. find({content:/^ work overtime /})

    13. Greater than, less than, not equal to:

      1. Find ({“field” : {$gt: value}}) // greater than: field > value
      2. Find ({“field” : {$lt: value}}) // Less than: field < value
      3. Find ({“field” : {$gte: value}}) // Greater than or equal to: field >= value
      4. Find ({“field” : {$lte: value}}) // Less than or equal to: field <= value
      5. Find ({“field” : {$ne: value}}) = value

    14. Include, not include:

      1. Db.spi. find({userid:{$in:[“1013″,”1014”]}})
      2. Db.spi. find({userid:{$nin:[“1013″,”1014”]}})

    15. Conditional connection:

      1. If we want a query that meets more than two criteria, we need to use the $and operator to associate the criteria. (and) phase when the SQL format for: $and: [{}, {}, {}], example: db. The spit. Find ({$and: [{visits: {$gte: 1000}}, {visits: {$lt: 2000}}]})
      2. $or:[{},{},{}] $or:[{},{},{}] db.spit.find({$or:[ {userid:”1013″} ,{visits:{$lt:2000} }]})

    16. Column value growth:

      1. Db.spi. update({_id:”2″},{$inc:{visits:NumberInt(1)}})

  3. Use MongoDB in Java code:

    1. Import maven dependencies:
    2. Query:
    3. Insert: