Idiot Programmer

  Check Constraint::   ->to check values before accepting into a column with user defined condition at column level:: ================ >create table test1(eid int check(eid<5),ename varchar2(10)); EX:: SQL> create table test1(eid int check(eid<5),ename varchar2(10)); Table created. SQL> insert into test1 values(1,'dan'); 1 row created. SQL> insert into test1 values(2,'sam'); 1 row created. SQL> select * from test1;        EID ENAME ---------- ----------          1 dan          2 sam SQL> insert into test1 values(5,'sam'); insert into test1 values(5,'sam') * ERROR at line 1: ORA-02290: check constraint (SYSTEM.SYS_C007650) violated SQL> insert into test1 values(4,'sam'); 1 row created. SQL> select * from test1;        EID ENAME ---------- ----------          1 dan          2 sam          4 sam SQL> insert into test1 values(55,'sam'); insert into test1 values(55,'sam') * ERROR at line 1: ORA-02290

 Not Null Constraint: ====================   -Restricted nulls but accepting duplicates      -Not null an not be applied at table level ex:: create table test1(eid int not null,ename varchar2(10) not null); EX:: SQL> create table test1(eid int not null,ename varchar2(10) not null); Table created. SQL> insert into test1 values(10,'raja'); 1 row created. SQL> insert into test1 values(20,'dan'); 1 row created. SQL> select * from test1;        EID ENAME ---------- ----------         10 raja         20 dan SQL> insert into test1 values(null,'dan'); insert into test1 values(null,'dan')                          * ERROR at line 1: ORA-01400: cannot insert NULL into ("SYSTEM"."TEST1"."EID") SQL> insert into test1 values(10,null); insert into test1 values(10,null)                             * ERROR at line 1: ORA-01400: cannot insert NULL into ("SYSTEM"."TEST1"."ENAME") SQL> select *

Unique Constraint:: ================  -Restricted Duplicates values but accepting nulls into a column column level:: ============ >create table test1(sno int unique,name varchar2(10) unique); EX:: SQL> create table test1(eid int unique,ename varchar2(10) unique); Table created. SQL> insert into test1 values(10,'virat'); 1 row created. SQL> select * from test1;        EID ENAME ---------- ----------         10 virat SQL> insert into test1 values(10,'rohit'); insert into test1 values(10,'rohit') * ERROR at line 1: ORA-00001: unique constraint (SYSTEM.SYS_C007643) violated SQL> insert into test1 values(20,'virat'); insert into test1 values(20,'virat') * ERROR at line 1: ORA-00001: unique constraint (SYSTEM.SYS_C007644) violated SQL> insert into test1 values(20,'rohit'); 1 row created. SQL> select * from test1;        EID ENAME ---------- ----------         10 virat         20 rohit SQL> insert into test1(null,'

 JDBC application For Delete Operation Create Table:: SQL> create table test1(eid int,ename varchar2(10)); Table created. SQL> insert into test1 values(1,'vijay'); 1 row created. SQL> insert into test1 values(2,'rajesh'); 1 row created. SQL> select * from test1;        EID ENAME ---------- ----------          1 vijay          2 rajesh SQL> commit; Commit complete. JDBC application::: import java.sql.*; class Test { public static void main(String[] args)throws Exception{ //load JDBC driver //get connection Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","system","tiger"); //create statement obj Statement st = con.createStatement(); //prepare and execute query String query = "delete from test1 where eid=2"; int count = st.executeUpdate(query); if(count==0){ System.out.println("No Row is deleted"); }else{ System.out.println(count+&qu

  JDBC Application For Insert Operation  For Explanation watch Video:: Create Table:: SQL>  create table test2(eid int,ename varchar2(10)); Table created. SQL> insert into test2 values(1,'vijay'); 1 row created. SQL> select * from test2;        EID ENAME ---------- ----------          1 vijay SQL> commit; Commit complete. Code:: import java.sql.*; class Test { public static void main(String[] args)throws Exception{ //load JDBC driver  Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","system","tiger"); //create statement obj Statement st = con.createStatement(); //prepare and execute SQL query String query = "insert into test2 values(2,'rajesh')"; //execute the query int count = st.executeUpdate(query); if(count==0){ System.out.println("No row inserted"); }else{ System.out.println("row is inserted"); } con.close(); }

  Hackerrank Solve Me First Solution - Java For Explanation Watch Video:: Code:: import java.io.*; import java.util.*; import java.text.*; import java.math.*; import java.util.regex.*; public class Solution {     static int solveMeFirst(int a, int b) {       // Hint: Type return a+b; below            return a+b;    }  public static void main(String[] args) {         Scanner in = new Scanner(System.in);         int a;         a = in.nextInt();         int b;         b = in.nextInt();         int sum;         sum = solveMeFirst(a, b);         System.out.println(sum);    } }

 Rename Command (DDL) in SQL Oracle With Implementation For explanation watch Video:: Rename command :: Used to change the name of table SQL> desc emp01;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  FNAME                                              VARCHAR2(15)  SAL                                                NUMBER(10) SQL> rename emp01 to emp02; Table renamed. SQL> desc emp01; ERROR: ORA-04043: object emp01 does not exist SQL> desc emp02;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  FNAME                                              VARCHAR2(15)  SAL                                                NUMBER(10)

 Average Population Hackerrank Solution SQL  For Explanation Watch Video:  Code:: select round(avg(population),0) from city;

 ALTER Command (DDL) in SQL Oracle with Implementation on ORACLE For Explanation Watch video: 1)Alter Modify :: to modify column name or datatype EX:: SQL> create table emp01(name char(10),sal Number(10)); Table created. SQL> desc emp01;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  NAME                                               CHAR(10)  SAL                                                NUMBER(10) SQL> alter table emp01 modify name varchar2(10); Table altered. SQL> desc Emp01;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  NAME                                               VARCHAR2(10)  SAL                                                NUMBER(10) SQL> alter table emp01 modify name varchar2(15)/*to change the size of varchar2*/; Table altered. SQL> desc emp01;  Name               

  Revising Aggregations - Averages Hackerrank Solution SQL  For Explanation Watch Video : Code:: select avg(population) from city where district = 'California';

 Create table in SQL For Explanation Watch Video:: EX:1: SQL> create table emp01(name varchar2(10),sal number(10)); Table created. How to see the Structure Of The table in SQL SQL> desc emp01;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  NAME                                               VARCHAR2(10)  SAL                                                NUMBER(10) EX2:: SQL> create table emp02(sno int,fname varchar2(10),lname varchar2(10),addr varchar2(10)); Table created. SQL> desc EMp02;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  SNO                                                 NUMBER(38)  FNAME                                           VARCHAR2(10)  LNAME                                           VARCHAR2(10)  ADDR                                              VARCHAR2(10)

JDBC basic example For Select Query  For explanation watch video:  For Creating Table:: SQL> create table emp60(srno int,fname varchar2(10)); Table created. SQL> desc emp60;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  SRNO                                               NUMBER(38)  FNAME                                              VARCHAR2(10) SQL> insert into emp60 values(1,'allu'); 1 row created. SQL> insert into emp60 values(2,'vijay'); 1 row created. SQL> insert into emp60 values(3,'rajni'); 1 row created. SQL> select * from emp60;       SRNO FNAME ---------- ----------          1 allu          2 vijay          3 rajni TO check Service Id: SQL> commit; Commit complete. SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- ORCL JDBC Program:: =========== import java.sql.*;

 Revising Aggregations - The Sum Function Hackerrank Solution SQL For Explanation Watch Video : Code:: select sum(population) from city where district = 'California';

  Connect n ropes with minimum cost Java Code Solution Watch Video:: Code: import java.util.*; import java.lang.*; import java.io.*; class Test{     public static void main(String[] args) {                  //Taking input using class Scanner         Scanner in = new Scanner(System.in);                  //Taking count of testcases         int t = in.nextInt();         while (t-- > 0) {                          //takling count of elements             int n = in.nextInt();                          //Creating an array of size n             long arr[] = new long[n];             //inserting elements to the array             for (int i = 0; i < n; ++i) arr[i] = in.nextLong();             //calling minCost method of class solve             System.out.println(new Solution().minCost(arr, n));         }     } } // } Driver Code Ends class Solution{     long minCost(long arr[], int n) {        PriorityQueue<Long> heap = new PriorityQueue<>();        for(int i=0;i<n;i++){      

 Hackerrank Super Reduced String Solution - JAVA For explanation watch Video :: Code: import java.io.*; import java.math.*; import java.security.*; import java.text.*; import java.util.*; import java.util.concurrent.*; import java.util.function.*; import java.util.regex.*; import java.util.stream.*; import static java.util.stream.Collectors.joining; import static java.util.stream.Collectors.toList; class Result {     /*      * Complete the 'superReducedString' function below.      *      * The function is expected to return a STRING.      * The function accepts STRING s as parameter.      */     public static String superReducedString(String s) {         StringBuilder sb = new StringBuilder(s);         for(int i=1;i<sb.length();i++){             if(sb.charAt(i)==sb.charAt(i-1)){                 sb.delete(i-1,i+1);                 i=0;             }         }         String ans = sb.toString();         if(ans.length()==0){             return "Empty String";        

 Revising Aggregations - The Count Function Hackerrank Solution SQL For Explanation Watch Video : Code: select count(*) from city where population > 100000;

 Type of Triangle Hackerrank Solution SQL  For Explanation Watch Video : Code: SELECT CASE WHEN A+B<=C OR B+C<=A OR C+A<=B THEN 'Not A Triangle' WHEN A=B AND B=C THEN 'Equilateral' WHEN A=B OR B=C OR C=A THEN 'Isosceles' ELSE 'Scalene' END FROM TRIANGLES;

 Employee Salaries Hackerrank Solution SQL For Explanation Watch Video:  Code: select name from Employee where salary>2000 and months < 10 order by employee_id;

Employee Names Hackerrank Solution SQL   For Explanation Watch Video : Code: select name from Employee order by name;

 Higher Than 75 Marks Hackerrank Solution SQL  for explanation watch Video: Code: select name from students where marks>75 order by substr(name,-3),id;

 Weather Observation Station 12 Hackerrank Solution SQL For Explanation Watch Videos:: Code: select distinct city from station where  not(city like 'A%' or city like 'E%' or city like 'I%' or city like 'O%' or city like 'U%') and not(city like '%A' or city like '%E' or city like '%I' or city like '%O' or city like '%U');

 Weather Observation Station 11 Hackerrank Solution SQL  For Explanation Watch video:: Code: select distinct city from station where not(city like 'A%' or city like 'E%' or city like 'I%' or city like 'O%' or city like 'U%') or not(city like '%A' or city like '%E' or city like '%I' or city like '%O' or city like '%U');

 Weather Observation Station 10 Hackerrank Solution SQL For Explanation Watch Video:: Code: select distinct city from station where not(city like '%A' or city like '%E' or city like '%I' or city like '%O' or city like '%U');

 Weather Observation Station 9 Hackerrank Soluion SQL For Explanation Watch Video:: Code: select distinct city from station where not(city like 'A%' or city like 'E%' or city like 'I%' or city like 'O%' or city like 'U%');

 Weather Observation Station 8 Hackerrank Solution SQL For Explanation Watch Video: Code: select distinct city from station where (city like 'A%' or city like 'E%' or city like 'I%' or city like 'O%' or city like 'U%') and       (city like '%A' or city like '%E' or city like '%I' or city like '%O' or city like '%U');

 Weather Observation Station 7 Hackerrank Solution SQL  For Explanation Watch Video: Code: select distinct city from station where (city like '%A' or city like '%E' or city like '%I' or city like '%O' or city like '%U');

 Weather Observation Station 6 Hackerrank Solution SQL  For Explanation Watch Video: Code: select distinct city from station where (city like 'A%' or city like 'E%' or city like 'I%' or city like 'O%' or city like 'U%');

 Weather Observation Station 5 Hackerrank Solution SQL  For Explanation Watch Video: Code: select(city), length(city) from station order by length(city),city limit 1; select(city), length(city) from station order by length(city) desc ,city limit 1;

 Weather Observation Station 4 Hackerrank Solution SQL For Explanation Watch Video: Code: select count(city) - count(distinct city) from station;

 Weather Observation Station 3 Hackerrank Solution SQL For Explanation Watch Video: Code: select distinct city from station where mod(id,2)=0;

 Weather Observation Station 1 Hackerrank Solution SQL For Explanation Watch Video: Code: select city,state from station;

 Japanese Cities' Names Hackerrank Solution SQL for Explanation Watch video: Code: select name from city where  COUNTRYCODE ='JPN';

 Japanese Cities' Attributes Hackerrank Solution SQL For Explanation watch video: Code: select * from city where COUNTRYCODE='JPN';

 Select By ID Hackerrank Solution SQL For Explanation Watch Video: Code: select * from city where id = 1661;

 Select All Hackerrank Solution SQL For Explanation Watch Video: Code: select * from city;

 Revising the Select Query II Hackerrank Solution SQL If You want Explanation Watch Video: Code: select name from city where population > 120000 and CountryCode = 'USA';

 *Oracle Supporting Data Types 1)Numeric Datatypes 2)Character/string 3)Long 4)Date 5)Raw & Long Raw 6)Lob (Large Object) ========================================================================= 1)Numeric DT: ============      i)INT      ii)Number i)INT:  =>To store Integer values Only =>when we use "int" DT at the time of table designing internally Oracle Server is converting into "Number" DT with max size 38 Digits.          int = Number(38) ii)Number(p,s):    =>To store Integer and float value         >Number(p) --------->INT         >Number(p,s)--------->Float    Precision(p): =============    =>Counting all digits (left + right) in the given Expression     ex:: i)98.34           precision = 4         ii)9878.34            precision = 6  scale(s): ========= =>Counting right side digit Only   ex:i)98.34        precision = 4        scale = 2      ii)8870.454        precision = 7         scale = 3 2)Character/string DT ==============

 Revising the Select Query I Hackerrank  Solution SQL  For Explanation Watch Video: Code: select * from city where population > 100000 and CountryCode = 'USA';

Birthday Cake Candles Hackerrank Solution Java For Explanation Watch Video: Sample Input 0 4 3 2 1 3 Sample Output 0 2 Code: import  java.io.*; import  java.math.*; import  java.security.*; import  java.text.*; import  java.util.*; import  java.util.concurrent.*; import  java.util.function.*; import  java.util.regex.*; import  java.util.stream.*; import   static  java.util.stream.Collectors.joining; import   static  java.util.stream.Collectors.toList; class  Result {      /*      * Complete the 'birthdayCakeCandles' function below.      *      * The function is expected to return an INTEGER.      * The function accepts INTEGER_ARRAY candles as parameter.      */      public   static   int  birthdayCakeCandles(List<Integer> candles) {      // Write your code here     Collections.sort(candles);      int  count =  1 ;      int  largest = candles.get(candles.size()- 1 );      for ( int  i=candles.size()- 2 ;i>= 0 ;i--){          if (candles.get(i)!=largest){             

 How to set classpath to access oracle driver  for Different Versions Of Oracle Software  For  More Details Watch Video: Solution: ====== setting classpath to access oracle driver ========================================= for different versions of Oracle ojdbc14.jar    -----> oracle 10g   ojdbc6.jar     -----> oracle 11g    ojdbc7.jar     -----> oracle 12c    ojdbc8.jar     -----> oracle 19c Step1 ::Go to The folder where you extract your Oracle Downloaded Zip File.             For Ex::I have Extracted Zip file in "C drive" in "App" Folder.         Step 2:: When We go to that folder then search for jar files acc. to your Oracle version           ojdbc14.jar    -----> oracle 10g           ojdbc6.jar     -----> oracle 11g           ojdbc7.jar     -----> oracle 12c           ojdbc8.jar     -----> oracle 19c For Ex::I have oracle 19c version so i will find for ojdbc8.jar simlarly you can find   ===================================================

 Maps-STL Hackerrank Solution C++ For Explanation Watch Video:: Sample Input 7 1 Jesse 20 1 Jess 12 1 Jess 18 3 Jess 3 Jesse 2 Jess 3 Jess Sample Output 30 20 0 Code: #include   < cmath > #include   < cstdio > #include   < vector > #include   < iostream > #include   < set > #include   < map > #include   < algorithm > using   namespace  std; int  main() {      /* Enter your code here. Read input from STDIN. Print output to STDOUT */          int  q;     cin>>q;     map<string, int >m;      int  type;     string name;      for ( int  i= 0 ;i<q;i++){         cin>>type>>name;          if (type== 1 ){              int  mark;             cin>>mark;             m[name] += mark;         } else   if (type== 2 ){             m.erase(name);         } else   if (type== 3 ){             cout<<m[name]<< "\n" ;         }     }      return   0 ; }

 Sets-STL Hackerrank Solution in C++ For Explanation Watch Video:: Sample Input 8 1 9 1 6 1 10 1 4 3 6 3 14 2 6 3 6 Sample Output Yes No No Code: #include <cmath> #include <cstdio> #include <vector> #include <iostream> #include <set> #include <algorithm> using namespace std; int main() {     /* Enter your code here. Read input from STDIN. Print output to STDOUT */      set<int>s;     int q;     cin>>q;     for(int i=0;i<q;i++){         int val;         cin>>val;         if(val==1){             int x;             cin>>x;             s.insert(x);         }else if(val==2){             int val;             cin>>val;             s.erase(val);         }else{             int val;             cin>>val;             auto it = s.find(val);             if(it!=s.end()){                 cout<<"Yes"<<endl;             }else{                 cout<<"No"<<endl;             }         }