Middleware is software that's assembled into an app pipeline to handle requests and responses. Each component: Chooses whether to pass the request to the next component in the pipeline. Can perform work before and after the next component in the pipeline…🤩🙌🏻”
.
.
.
📍Follow 👉🏼 @Coder_Baba
.
.
.
📍Follow 👉🏼 @Coder_Baba
🎯Important SQL Interview Question:
🔰Q. What are the different types of indexes?
Ans:
✅An index is a performance tuning method of allowing faster retrieval of
records from the table. An index creates an entry for each value and makes
it faster to retrieve data.
There are three types of indexes:
1️⃣Unique Index: This indexing does not allow the field to have duplicate
values if the column is unique indexed. Unique index can be applied
automatically when primary key is defined.
2️⃣Clustered Index: This type of index reorders the physical order of the
table and search based on the key values. Each table can have only one
clustered index.
3️⃣Non-Clustered Index: Non-Clustered Index does not alter the physical
order of the table and maintains logical order of data. Each table can
have 999 nonclustered indexes.
🔰Q.What is a cursor in SQL?
✅A database Cursor is a control which enables traversal over the rows or
records in the table. This can be viewed as a pointer to one row in a set of
rows. Cursor is very much useful for traversing such as for retrieval, addition
and removal of database records.
🔰Q.What is a trigger?
✅A DB trigger is a code or programs that automatically execute with response
to some event on a table or view in a database. Mainly, trigger helps to
maintain the integrity of the database.
Example: When a new student is added to the student database, new
records should be created in the related tables such as the Exam, Score and
Attendance tables.
🔰What are constraints?
✅Constraint can be used to specify the limit on the data type of table.
Constraint can be specified while creating or altering the table statement.
🔰Q. What is data integrity?
✅Data Integrity defines the accuracy and consistency of data stored in a
database. It can also define integrity constraints to enforce business rules
on the data when it is entered into the application or database.
🔰Q What is auto increment?
✅Auto increment keyword allows the user to create a unique number to be
generated when a new record is inserted into the table. AUTO INCREMENT
keyword can be used in Oracle and IDENTITY keyword can be used in SQL
SERVER.
🔰Q. What is a data warehouse?
✅Data warehouses are a central repository of data from multiple sources of
information. This data is consolidated, transformed and made available for
the mining and online processing. Warehouse data have subsets of data
called Data Marts.
🔰Q. What is the difference between DROP and TRUNCATE statements?
✅TRUNCATE removes all the rows from the table, and it cannot be rolled
back. DROP command removes a table from the database and operation
cannot be rolled back.
🔰Q. What are aggregate and scalar functions?
✅Functions are methods used to perform data operations. SQL has many inbuilt functions used to perform string concatenations, mathematical
calculations etc.
SQL functions are categorized into the following two categories:
Aggregate Functions and Scalar Functions.
Aggregate SQL Functions-
The Aggregate Functions in SQL perform calculations on a group of values
and then return a single value. Following are a few of the most commonly
used Aggregate
SUM(), COUNT(), AVG(), MIN(), MAX(), FIRST() & LAST()
The Scalar Functions- in SQL are used to return a single value from the given
input value. Following are a few of the most commonly used Scalar
LCASE(), UCASE(), LEN(), MID(), ROUND(), NOW(), FORMAT()
🔰Q.What is alias in SQL?
✅SQL aliases are used to give a table, or a column in a table, a temporary
name. Aliases are often used to make column names more readable. An
alias only exists for the duration of that query. An alias is created with the
AS keyword
Follow for more @Coder_Baba
#Coderbaba #CSharpTutorials #SQL
🔰Q. What are the different types of indexes?
Ans:
✅An index is a performance tuning method of allowing faster retrieval of
records from the table. An index creates an entry for each value and makes
it faster to retrieve data.
There are three types of indexes:
1️⃣Unique Index: This indexing does not allow the field to have duplicate
values if the column is unique indexed. Unique index can be applied
automatically when primary key is defined.
2️⃣Clustered Index: This type of index reorders the physical order of the
table and search based on the key values. Each table can have only one
clustered index.
3️⃣Non-Clustered Index: Non-Clustered Index does not alter the physical
order of the table and maintains logical order of data. Each table can
have 999 nonclustered indexes.
🔰Q.What is a cursor in SQL?
✅A database Cursor is a control which enables traversal over the rows or
records in the table. This can be viewed as a pointer to one row in a set of
rows. Cursor is very much useful for traversing such as for retrieval, addition
and removal of database records.
🔰Q.What is a trigger?
✅A DB trigger is a code or programs that automatically execute with response
to some event on a table or view in a database. Mainly, trigger helps to
maintain the integrity of the database.
Example: When a new student is added to the student database, new
records should be created in the related tables such as the Exam, Score and
Attendance tables.
🔰What are constraints?
✅Constraint can be used to specify the limit on the data type of table.
Constraint can be specified while creating or altering the table statement.
🔰Q. What is data integrity?
✅Data Integrity defines the accuracy and consistency of data stored in a
database. It can also define integrity constraints to enforce business rules
on the data when it is entered into the application or database.
🔰Q What is auto increment?
✅Auto increment keyword allows the user to create a unique number to be
generated when a new record is inserted into the table. AUTO INCREMENT
keyword can be used in Oracle and IDENTITY keyword can be used in SQL
SERVER.
🔰Q. What is a data warehouse?
✅Data warehouses are a central repository of data from multiple sources of
information. This data is consolidated, transformed and made available for
the mining and online processing. Warehouse data have subsets of data
called Data Marts.
🔰Q. What is the difference between DROP and TRUNCATE statements?
✅TRUNCATE removes all the rows from the table, and it cannot be rolled
back. DROP command removes a table from the database and operation
cannot be rolled back.
🔰Q. What are aggregate and scalar functions?
✅Functions are methods used to perform data operations. SQL has many inbuilt functions used to perform string concatenations, mathematical
calculations etc.
SQL functions are categorized into the following two categories:
Aggregate Functions and Scalar Functions.
Aggregate SQL Functions-
The Aggregate Functions in SQL perform calculations on a group of values
and then return a single value. Following are a few of the most commonly
used Aggregate
SUM(), COUNT(), AVG(), MIN(), MAX(), FIRST() & LAST()
The Scalar Functions- in SQL are used to return a single value from the given
input value. Following are a few of the most commonly used Scalar
LCASE(), UCASE(), LEN(), MID(), ROUND(), NOW(), FORMAT()
🔰Q.What is alias in SQL?
✅SQL aliases are used to give a table, or a column in a table, a temporary
name. Aliases are often used to make column names more readable. An
alias only exists for the duration of that query. An alias is created with the
AS keyword
Follow for more @Coder_Baba
#Coderbaba #CSharpTutorials #SQL
🚀Java Variable:
1, Variable is the name of a memory location in which we can store the value.
2, The variable value can be change.
3, A variable is defined by combining an identifier, data types, and an initializer.
4, The first character in the variable name must be an alphabet, underscore, a digit, or a dollar sign. 5, All variables have a scope
6, The identifier is the name of the Variable.
7, Commas or blanks are not used inside a variable name.
🚀Java Variable Declaration Syntax :
Type Variable name;
int is a type
a ,b and a*b is a variable-name
Java variable declaration syntax Rules:
Type Variable name:
int Roll_No; //Roll_No declare a Variable
float Percentage; //Percentage declare a Variable
Roll_No=40 ; //assigns value in variable
Precentege=40.80; //assigns value in variable
How to Declare a variables in Java?
The Variables are declared in various types:
int abc;// this declare a variable
int abc;// (abc and a_bc are a variable)
int a,b,x,z;// (a,b,x,z) are a variable
byte a1=40;//initialize a.
double a2=40.80 ;//like a float
Char a3=“ram”;//a variable gain value ( ram )
Q-Addition of Variables Java Example?
int a,b,c,d;
a=10; b=20; c=30; d=40;
System.out.println(a+b+c+d);
Output :
100
Q-Variable increment values in Java?
int a=10;// a is a Variable
a+=40;
a=a+20;
System.out.println(a);
Output :
70
Q-Create a variable and store a no inside this variable and print output?
int a;
a=40;
OR
int a=40;
System.out.println(a);
int a;
a=40;
Output :
40
Q-Create a string variable and store a no inside string type variable and print output?
String a="Ram ";
String b="Lakshman ";
OR
String a,b;
a="Ram ";
b="Lakshman ";
System.out.println(a+b);
Output :
RamLakshman
Constant:
Constant is used when you store a value inside a variable, but use Constant after you can’t overwrite the existing deal.
1, Variable is the name of a memory location in which we can store the value.
2, The variable value can be change.
3, A variable is defined by combining an identifier, data types, and an initializer.
4, The first character in the variable name must be an alphabet, underscore, a digit, or a dollar sign. 5, All variables have a scope
6, The identifier is the name of the Variable.
7, Commas or blanks are not used inside a variable name.
🚀Java Variable Declaration Syntax :
Type Variable name;
int is a type
a ,b and a*b is a variable-name
Java variable declaration syntax Rules:
Type Variable name:
int Roll_No; //Roll_No declare a Variable
float Percentage; //Percentage declare a Variable
Roll_No=40 ; //assigns value in variable
Precentege=40.80; //assigns value in variable
How to Declare a variables in Java?
The Variables are declared in various types:
int abc;// this declare a variable
int abc;// (abc and a_bc are a variable)
int a,b,x,z;// (a,b,x,z) are a variable
byte a1=40;//initialize a.
double a2=40.80 ;//like a float
Char a3=“ram”;//a variable gain value ( ram )
Q-Addition of Variables Java Example?
int a,b,c,d;
a=10; b=20; c=30; d=40;
System.out.println(a+b+c+d);
Output :
100
Q-Variable increment values in Java?
int a=10;// a is a Variable
a+=40;
a=a+20;
System.out.println(a);
Output :
70
Q-Create a variable and store a no inside this variable and print output?
int a;
a=40;
OR
int a=40;
System.out.println(a);
int a;
a=40;
Output :
40
Q-Create a string variable and store a no inside string type variable and print output?
String a="Ram ";
String b="Lakshman ";
OR
String a,b;
a="Ram ";
b="Lakshman ";
System.out.println(a+b);
Output :
RamLakshman
Constant:
Constant is used when you store a value inside a variable, but use Constant after you can’t overwrite the existing deal.
Good Morning All,
New Post on Instagram
👇Check 👇 out 👇this
What is Cookies in JavaScript
https://www.instagram.com/p/Cr2E2KTBUS5/?utm_source=ig_web_copy_link
New Post on Instagram
👇Check 👇 out 👇this
What is Cookies in JavaScript
https://www.instagram.com/p/Cr2E2KTBUS5/?utm_source=ig_web_copy_link
10 Subreddits You must Join on Reddit if you are a Data Science, Machine Learning, Deep Learning or Artificial Intelligence Enthusiast :
01. reddit.com/r/datascience/
02. reddit.com/r/MachineLearning/
03. reddit.com/r/learnmachinelearning/
04. reddit.com/r/LanguageTechnology/
05. reddit.com/r/deeplearning/
06. reddit.com/r/datasets/
07. reddit.com/r/visualization/
08. reddit.com/r/dataisbeautiful/
09. reddit.com/r/learnpython/
10. reddit.com/r/rstats/
01. reddit.com/r/datascience/
02. reddit.com/r/MachineLearning/
03. reddit.com/r/learnmachinelearning/
04. reddit.com/r/LanguageTechnology/
05. reddit.com/r/deeplearning/
06. reddit.com/r/datasets/
07. reddit.com/r/visualization/
08. reddit.com/r/dataisbeautiful/
09. reddit.com/r/learnpython/
10. reddit.com/r/rstats/
Reddit
Data Science
A space for data science professionals to engage in discussions and debates on the subject of data science.