Why should we prefer Mongo DB instead of SQL Server?
SQL Server / Relational Database
- Relational Database are organised by tables, the data is stored in the form of rows and columns.
- Keys are used to tie the data between different tables.
- Relational database can be relatively very complex for the simple schema like getting the info of single user we need to combine multiple tables as shown below,
- Creating relational database schema can have several disadvantages, like the design can be complex, etc.
- Changes to schema can require the changes for the entire database.
- Complex queries to join the data.
Mongo DB / NO-SQL
- Mongo DB is NO-SQL database which have the data in JSON format.But internally it is stored in BSON (Binary JSON).
- A document related database contains all the required information in the same object, that makes the job easy for us.
- Mongo DB are mostly used when the amount of data is really large and Relational database becomes slow.
- In Mongo DB we have Collections — Tables(in relational database), Documents — Rows(in relational database) and Key Value pairs as in JSON object.
- A JSON object is easy to understand.
Let’s get started with Mongo now,
Download and install the mongo DB community edition from — https://www.mongodb.com/
Once the setup is completed open CMD in C:\Program Files\MongoDB\Server\4.2\bin and in CMD enter the command
md \data\db
This command is used because mongo db needs a data directory to store all the data. By default mongo’s data directory path is the absolute path \data\db. so we create that directory to store the data.
- Start Mongo db using command,
"C:\Program Files\MongoDB\Server\4.0\bin\mongod.exe"This starts the main mongo db database process.
- Now open another command prompt and connect the mongo db using the command,
"C:\Program Files\MongoDB\Server\4.0\bin\mongo.exe"Now we can enter the mongo db commands and play with it. Let’s see how,
- To get the list of DB’s we can give the command,
show dbs
- Now Say we want to use TMS DB we can give the command like use TMS, if the database name does not exists then it creates a new database with the name we give in use dbname command.
- To see the collections in the database give show collections command.
- Now we can see the logs collection with the command — db.logs.find({}) . This will find all the key value pairs in logs table.
- To Insert a new log we can use — db.sample.insertOne({“Name”:”Lokesh”,”City”:”Chennai”}), This will insert a new records with the fields name and city in sample collection
By default the mongo db inserts a key, if it is not added by the user. It is unique for each entry.
- To Update the city we can use the command — db.sample.updateOne({“Name”:”Lokesh”}, {$set:{“City”:”Mumbai”}}). This will update the city for name Lokesh as Mumbai
- To drop sample collection we can use — db.sample.drop().
These are the basic operations with mongo, I will be posting more about Mongo in the upcoming stories!!
