Idiot Programmer

 Drop Command (DDL) in SQL Oracle With Implementation For Explanation Watch Video:: Drop Command Used to delete  table (rows X columns) EX::: 1)Create table SQL> create table emp01(fname varchar2(15),sal Number(10)); Table created. 2)Describe table SQL> desc emp01;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  FNAME                                              VARCHAR2(15)  SAL                                                NUMBER(10) SQL> select * from emp01; no rows selected 3)Insert values into table SQL> insert into emp01 values('smith',500000); 1 row created. 4)Drop the table SQL> drop table emp01; Table dropped. 5)TO see columns deleted again describe table SQL> desc emp01; ERROR: ORA-04043: object emp01 does not exist 6_to see data deleted SQL> select * from emp01; select * from emp01               * ERROR at line 1: ORA-00942: table or view does not exist

 Truncate Command (DDL) in SQL Oracle With Implementation For Explanation Watch Video:: Truncate:    -TO delete all rows from table at a time    - Deleting rows but not column    - By using this cmd we cant delete specific row from table    -It doesnt support where clause EX::: SQL> create table emp01(fname varchar2(10),sal Number(10)); Table created. SQL> insert into empo1 values('miller',500000); insert into empo1 values('miller',500000)             * ERROR at line 1: ORA-00942: table or view does not exist SQL> insert into emp01 values('miller',500000); 1 row created. SQL> insert into emp01 values('Baburao',50000); 1 row created. SQL> insert into emp01 values('Smith',500000); 1 row created. SQL> select * from emp01; FNAME             SAL ---------- ---------- miller         500000 Baburao         50000 Smith          500000 SQL> truncate table emp01; Table truncated. After Truncate:: SQL> select * from emp01; no rows se

 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)

 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