Schema

Figure 822. Schema validation support

db.runCommand( {
  collMod: "group",
  validator: { $jsonSchema: {
     bsonType: "object",
     required: [ "cname", "gid" ],
        properties: {
          cname: {
              bsonType: "string",
              description: 
              "A group's common name"
          },

          gid: {
             bsonType: "string",
             description: 
             "A group's short name"
          }
       }
     } 
  },
  validationLevel: "moderate"
})

Figure 823. Violating required field

db.group.insert(
 {
   cname: "Extra users"
 }

... Bulk write operation error on server localhost:27017. 
Write errors: [BulkWriteError{index=0, code=121,
    message='Document failed validation', details={}}].

Figure 824. Schema types

See BSON Types for reference.

Figure 825. Enforcing unique keys

db.group.createIndex({ 
   "cname": 1
  },
  {
      unique: true
})

db.group.insert({cname: "Extra users",
  ...
  }
)

com.mongodb.MongoBulkWriteException:
Bulk write operation error on server localhost:27017.
Write errors: [BulkWriteError{index=0, code=11000, 
message='E11000 duplicate key error collection: 
exploredb.group index: cname_1 dup key: 
  { cname: "Extra users" }', details={}}].

Figure 826. On the downside

No way to enforce referential integrity rules.

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