MongoDB Database Basic Operations

MongoDB in a Clustered collection (Collection/coll) equivalent to a table in MySQL

The document is equivalent to every row of data in MySQL

Common commands

1. Get Help commands

Db.help () db. Table name. Help () db. Table name. Find (). Help () Rs.help ()

2. Switch/CREATE Database

Use database name NOTE: MongoDB database can be used first, then created, when creating a collection (table), the current database will automatically create an example: There is a database for SUTDENTDB, to switch to this database is: use Studentdb

3. Querying all databases

Show DBS Example:> show Dbsadmin 0.078GBlocal 0.078GBstudentdb 0.078GBtest 0.078GB

4. Delete the currently used database

Db.dropdatabase () example:> use testswitched to DB test> db.dropdatabase () {"Dropped": "Test", "OK": 1}> show Dbsadm In 0.078GBlocal 0.078GBstudentdb 0.078GB

5. View the currently used database

Db.getname () example:> use studentdbswitched to DB studentdb> db.getname () studentdb

6. Display the current DB status

Db.stats ()

7. Current DB version

> db.version () 2.6.12

View basic information for a clustered collection (table)

1. View Help

db. Table name. Help ()

2. Query the number of data bars in the current collection

db. Table name. COUNT ()

3. View the size of the data space

db. Table name. DataSize ()

4. The database where the current aggregation collection resides

db. Table name. GETDB ()

5. Get the status of the current aggregation collection

db. Table name. Stats ()

6. Get the total size of the aggregation collection

db. Table name. TotalSize ()

7. View the aggregate collection storage space size

db. Table name. Storagesize ()

8. View Shard Version Information

db. Table name. Getshardversion ()

9. Renaming a Clustered collection

db. Table name. Renamecollection ("new name")

10. Delete the current clustered collection

db. Table name. Drop ()

Query operations

1. Querying All Records

db. Table name. Find () is equivalent to: select* from table name; The default is 20 records per page, and if not, you can query the next page of data with it iteration commands. Note: Type the IT command cannot take ";"

2. The query results filter out duplicate data in a field and then display it

db. Table name. DISTINCT ("field name") Example:> db.student.distinct ("Age") [20, 40] Note: The data in the age field in the student table is removed and displayed

3. Querying the AGE=22 data

db. Table name. Find ({"Age": 22}) Example:> Db.student.find ({"Age": +}) {"_id": ObjectId ("5740dcb29bc83e10802f1cd8"), "name": " Kity "," age ": +," gender ":" Womand "}

4. Querying the AGE>22 data

Greater than sign $GT > db.student.find ({"Age": {$gt: +}}) {"_id": ObjectId ("5740c1419bc83e10802f1cd6"), "name": "Tom", "age": 23, "Gender": "Male"} {"_id": ObjectId ("5740dc369bc83e10802f1cd7"), "name": "Jerry", "Age": $, "gender": "Male", "Guoji ":" China "} {" _id ": ObjectId (" 5742263773344acd707888ba ")," name ":" Gu Zenghui "," age ": +," gender ":" Male "," Course ":" Linux "}

5.

MongoDB Database Basic Operations