PL/SQL Programming Minute

1. Basic operation

SQL>sqlplus /nolog

SQL>conn / as sysdba

SQL>alter user hr account unlock

SQL>alter user hr identified by hr

SQL>grant DBA to hr

SQL>conn hr/hr

Select * from user_tables

Select * from dba_tables

SQL>revoke dba from hr

SQL>host dir drop*

select first_name ||','|| last_name  from employees;

NVL: Set the value for NULL

NVL (name,'no name')

NVL (base_salary, 2000)

Display the table structure:

DESC employees;

2. SQL Plus

sqlplus [username[/password][@database]]]

connect scott/tiger@ora92

DEFINE: Declare a variable,short :DEF

DEFINE _EDITOR=vi

DESCRIBE: Lists the attributes of tables and other objects. short:DESC

show all: Display environment variable

SET: Modify the SQLPlus environment variable

SET SERVEROUT ON|OFF

SET ECHO ON|OFF

SET PAGE

SET TIME ON|OFF

SAVE D:\sql_name.sql

get D:\sql_name.sql

ed[it] D:\sql_name.sql

@D\sql_name.sql

rem

set pagesize n

set linesize n

select sysdate from dual;  Get the system date