SQL: From Basics to Advanced+ Sql interview(Beginner to Pro)
Description
Why SQL Store large number of records Share huge data set among many people Add and edit data easily Quick and easy to find information RDBMS TERMINOLOGY Column as Attribute Row as Entity Instance Table as Entity AlternateKey as UniqueKey RELATIONSHIPS Cardinality 90% of the tables in database will be linked with another tables. 10%of the tables will be independent. There are three types of relationships between tables one to one one to many many to many Tables can have a single / multiple relationships or may not have relationships. Structured data - 2 dimensional data Rows,Columns PrimaryKey in one table will be given as ForiegnKey in another table to build relationship. DATA MODELING RDBMS PrimaryKey & ForiegnKey with relationship between them. 1 to 1 - any PrimaryKey can become ForiegnKey 1 to many employees in a department PK of parent table will be FK in child table Department table Deptid(PK),DeptName, Employees Table Empid,EmpName,DeptId(FK) many to many(students and teachers,patients & doctors,Hospital & Doctors)(TeacherId,TeacherName)(StudentId,StudentName,TeacherId) New table will be created and extra column will be added(Bridge Table) Patient Table(PatientNo(PK),PatientName,Adress), Doctors Table(DoctorNo(PK),Name,Qualification,Salary, DateOfJoining, DateOfResigning) Patient Doctor Table() SDLC-Software Development Life Cycle Requirement Analysis & Design Development Testing Release Domain expert(SRS documentation) Architect SQL developers Testers Deployers(TL/Manager) ERD(Entity Relationship Diagram) Peter Chan-Used to design Database Referential Integrity SQL server performs existence check when we create relationship. SELF REFERENTIAL TABLES A table which has both PrimaryKey and ForiegnKey in it & ForiegnKey refering the primary key in the same table. You are going to learn commands (DDL,DML,DQL,DCL,TCL) datatypes constraints CONSTRAINS Null Default PrimaryKey UniqueKey ForiegnKey Check Auto Increment views operators query writing joins sub query derived table Views Indexes Stored Procedures Triggers Functions Cursors
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