This tutorial gives you for
learning on Structured
Query Language and it
helps you to perform on SQL commands which provide instant result.
SQL
SQL is a language for database;
SQL stands for Structured Query Language;
it is used for storing, retrieving and manipulating data in relational
databases.
SQL Language/Commands
SQL Language/commands are used to perform various functions.
These functions include building database objects, manipulating objects, loading
data to database tables, updating existing data in tables, deleting data,
performing database queries, controlling database access, and overall database
administration.
SQL Server Architecture
SQL Server Architecture is built with the following major
components.
1.
The Network Interface Layer
2.
Relational Engine
3.
Storage Engine and
4.
SQL OS
SQL Processing Architecture
SQL
Processing Architecture represents how Microsoft SQL Server queries are
processed on the client, how the various clients interact with SQL Server, and
what SQL Server does to process clients' requests. The high-level diagram is
given below. Let’s understand more details on this topic, refer the following
link.
The Optimizer will try to find the most efficient way/plan to execute the query based on available information such as table Index and scanning mechanism.
The Query execution default order is
1. FROM clause
2. WHERE clause
3. GROUP BY clause
4. HAVING clause
5. SELECT clause
6. ORDER BY clause
RDBMS
RDBMS stands for Relational Database Management System; it is a database
management system (DBMS) that is called RDBMS that is supported by E. F. Codd
rules. (https://en.wikipedia.org/wiki/Codd%27s_12_rules)
Table
Table (entity) is
a collection of related data entries and it consists of columns and rows.
Example:
Employee, Department..,
Attribute
An attribute is a specification that defined a property an object, element, or file. An attribute of an object usually consists of a name and a value; of an element, a type or class name; of a file, a name and extension.
Example: EmployeeName, EmployeeAge, DepartmentName, ..,
Field
A field is an attribute of a table that is designed for specific information about each record/row in the table.
Example: EmployeeName, EmployeeAge, DepartmentName, ..,
Column
A column is a field in a table that maintains specific field information about each record/row in the table.
Example: EmployeeName, EmployeeAge, DepartmentName ..,
Row
Row is also called as a record or tuples of a table.
Data Type
A data type in a programming language is a set of data with values having predefined characteristics.
Examples: integer, floating point unit number, character, string, and binary etc..,
NULL
NULL value is a field with no value (Unknown data, OR Not applicable OR Data not given)
Index
An Index is a data
structure that improves the speed/fast of data retrieval on a database
table.
View
A View in SQL is a logical subset of data from one or more tables.
Synonym
A Synonym
is an alias for a database object (table, view, procedure, function, etc..,)
Cursor
A Cursor is a database
objects to retrieve data from a result set one row at a time.
Stored Procedure
A Stored
Procedure is a set of Structured Query Language (SQL) statements with an
assigned name that's stored in the database in compiled form so that it can be
shared by a number of programs.
Function
A Function
is same as a stored procedure that must return a value.
Trigger
A Trigger is a special kind of stored
procedure that automatically executes when an event occurs in the database
server.
Constraints
Constraints are
the rules enforced on data columns on a table which ensures the accuracy and
reliability/maintain the integrity of the data in the database.
Integrity
Integrity ensures the accuracy and reliability of the data in
the database
Normalization
Database normalization, or normalization, is
the process of organizing the columns (attributes) and tables (relations) of a
relational database to reduce data redundancy and improve data integrity.
Entity Relationship Model
Entity Relationship Model is a logical relationship of
entities (or objects) in order to create a database.
Entity Relationship Diagram (ER Diagram)
Entity
Relationship Diagram is a graphical representation of logical relationship
among entities (tables) in the database.
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