Terminology of Mongoose
Mongoose will use the terms Schema and Model. While doing any operation, in this entire tutorial we will use the terms 'Schema' and 'Model' frequently so we need to know. lets know those
What is Schema?
"Mongoose Schema
will create a mongodb collection and defines the shape of the
documents within that collection".
If we want to
create a mongodb collection in a structured manner similar to
SQL tables then we can do that using mongoose Schema.
In the schema
creation we will specify the details of fields like field name,
its type, default value if need, index concept if need,
constraint concept if need.
Like
var userSchema = new Schema({
userid : String,
chips : {type:double, default:0.0},
regdate : {type:Date, default: Date.now,required:true}
})
Simply Schema creation is similar to table creation of SQL.
Note:-
- A Schema can contains static methods
- A Schema can contains non-static(instance) methods
- A Schema can contains indexes
Check this link for "How to create Methods, Indexes for Schema's"
Model:-
Schemas define a
structure we will apply that Schema part to a model, means "Models are the constructors compiled from our
schema definitions".
Instances of
these models represent documents which can be saved and
retrieved from our database. All document creation and retrieval
from the database is handled by these models.
We can create the
Models using mongoose.model() constructor as
var modelinstance= mongoose.model('collection-name',schemaname);
for the above 'userSchema' example check the model creation
var userModel = mongoose.model('users',userSchema);
How to create document
instances using model's
var docinstance = new modelinstance(values for schema );
Example:-
var alex = new userModel({userid:'Alex',chips:10000,regdate:Date.now});
var michal = new userModel({userid:'Michal' });
See CRUD opertions; of model for detail discussion on models concept.