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What is database: database is a storage system taht has a collection of data. Types of database: 2 types : 1RBBMS:-relational database store in form of tables, that can easily retrived, managed,and update. 2.Non-RDMS:-non relational database store data in the form document,graph. What is Sql:- sql is relational databse. sql structured query language: sql is a language to communicate with database. sql command help you to store ,process ,analyze and manipulate database. What is difference between sql and Nosql sql: 1 sql is relational database 2.data store in tables 3.databases have fixed or static or predefine schema. 4.low performance with huge volumes of data. 5.ex:-mysql,db2 , oracle,sql-server. nosql: 1. it is non relational database. 2. data store in the key:value, document,graph. 3. they have dynamic schema. 4. Easily works with huge volumes of data 5. exa:mongodb 4 types of sql commands: 1.Data Defination language:DDL create,alter,Drop,Truncate. 2. Data manipulation language:DML select , insert,Update,delete 3. Data control language: DCL grant, revoke 4. Trasaction control language:TCL commit, rollback Data Types: Datatypes of a column defines what value the column can store in table. Data type mailty classified into three categories: 1. numeric datatype:int ,float,bool, bigint,double. 2.string datatype: char, varchar 3.date &time: date,datetime,timestamp.
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