Oracle

When it comes to soft parsing (soft prase) and hard prase, it is impossible to talk about Oracle's handling of SQL. When you issue an SQL statement to Oracle, Oracle performs several steps in this SQL process before executing and getting results:1,

User's login:[Username/password] [@server] [As Sysdba/sysoper] Example: Sys/pass as SysdbaUser's switchover:[Connect] [Username/password] [@server] [As Sysdba/sysoper] Example: Connect system/passShow currently logged in User:Show userDisplay the

Oracle Learning Series 7************************************************************************************constraint on the associated table: forcibly delete the parent table from the associated table: DROP table tab_name cascade constraint; The

Select ' Drop table ' | | table_name | | ' "; ' | | Chr (13) | |  Chr (from User_tables); --delete tablesSelect ' Drop View ' | | view_name| | ' "; ' | | Chr (13) | |  Chr (from User_views); --delete viewsSelect ' Drop sequence ' | | sequence_name| |

package cn.com.login.dao;import java.sql.connection;import java.sql.drivermanager;import  java.sql.preparedstatement;import java.sql.resultset;public class logindao {     public string getusername (String usercode) {    connection 

1. FunctionsCreate or Replace function Gettablecount (table_name VARCHAR2) return number asBeginDECLARE sql_query VARCHAR2 (300);T_count number;Begin 　　　　　　Sql_query:= ' SELECT COUNT (*) from ' | |   table_name; There is a space behind the

1. Use logical operation symbolsQuestion: Query for wages higher than 500 or job manager employees, but also to meet their initials in uppercase J?SELECT * from emp where (Sal > $ or job = ' MANAGER ') and ename like ' j% ';2. Use the ORDER BY

The basic syntax of Wm_concat Select Proj_id,max (scale_valus) as Scale_valusFrom (select a.proj_id,Wm_concat (A.scale_valu) over (partition by a.proj_id ORDER by A.ym) as Sccale_valusFrom S_proj_ees_scale Awhere a.ym between ' 201601 ' and ' 20

External Association is a proprietary statement of the Oracle databaseThe left Outer join is the standard statement of the SQL-92These two SQL are generally considered to be equivalent, but there are some subtle differences.In general, the

One. Server local installation oracle11g or 10GTwo. Create a tablespace in the run input sqlplus/nolog,oracle.Three. After the installation is complete, enter SQL developer in the run to open SQL Developer (this is the native)Four. Select the JDK

The following document DBCA the process of creating the main library, with pictures in each of the basic steps. Oracle User Execution DBCA, if it is the root user login graphics surface, the SU switch user before need to execute a xhost +x,

recently the system often locks the table every day, and after the process has been killed, it is locked again soon. (a) First post the process of the scene to deal with the deadlock.In addition: Sometimes the kill session through PL/SQL may still

SQL statements are executed serially on a single CPU (Serial), even if there are multiple CPUs in the system, and an SQL statement cannot take advantage of them. This allows a CPU to use resources that determine the performance of the SQL statement.

installing sqldevelo per Connect Oracle ---- ( This installation method is always in windoxs32bit ) Uploaded http://down.51cto.com/data/2213695Installing sqldeveloer is a prerequisite for installing Java and setting up environment variables.1.

--declaring cursors; cursor cursor_name is select_statement--for Loop Cursors--(1) Defining cursors--(2) Defining cursor variables--(3) Use this cursor with a for loop declare cursor yy is select * from mytest; C_row yy % rowtype; begin

Understanding the PGAPGA (Program Grlobal areas or process global area) refers to the private memory space of the service process, including the service process global variables, data structure and control information, such as cursors for the

I. DML operations on a view1. Create a View V_personCreate or replace noforceview V_personAs Select * from the person where ID between 1003 and 1007;2. Insert operation into view V_personInsert into V_person (id,name) values(1010, ' J ')"Note" The

To create a user:1,sqlplus sys/pwd as sysdba;2, create userusernameIdentified byPassword; 3, Grant Dba,connect,resource tousername;To View table space usage:Select UPPER (f.tablespace_name) "Table space name",D.TOT_GROOTTE_MB "Table space size

Problem Description:Using POWERDESIGNER15 to create a physical data model for Oracle 11g, you want to implement a field that is self-increasing using the following steps:1, create a sequence, named Sequence_1;2, in the Self-increment field edit

0006 notes 02-calculation fields and functions, and 02- 1. The data retrieved from the database is often not in the final format to be displayed. The data can be converted and formatted in the database or client application, but generally, it is