Oracle

  Solution for Oracle to forget the user name and password Operating System: windows xp Oracle 10.1.0.2.0 I have not installed Oracle for a long time, and the password changed by sys and system is also forgotten. Therefore, the following solution is

The two highly lethal commands compiled today can instantly kill Oracle. Next I will give a simple comment and demonstrate its power.$ Ps-ef | grep $ ORACLE_SID | grep-v grep | awk '{print $2}' | xargs kill-9$ Ipcs-m | grep oracle | awk '{print $2}'

Hash join is a very powerful function in oracle. When used as hash join, oracle selects a table as the driving table and first removes unnecessary data according to the filter conditions, then, make the result set into a hash table, put it into the

Indexes are often created to improve data access efficiency. However, each index reconstruction operation slows down when the data volume is large, affecting the processing efficiency. Therefore, for a large amount of data, it is often used to

ORA-06502: PL/SQL: Number or value error: string buffer is too smallWe usually use a where statement to query a database. However, we are not sure about the content of the where statement (for example, it needs to be determined at runtime, that is

Concept:A view is only a select statement, which is fully logical and non-physical. It is also called a virtual table. Secure, convenient, and consistentCase 1: Create a viewCreate or replace view myviewAsSelect * from qwe;Case 2 call View:Select *

When you edit a row, you will inevitably encounter switching rows. In this case, you need to kindly prompt whether to save the data of the current row and then switch. A switching row event is required. When PopUp pops up, the rollback is triggered

I used oracle time comparison today. I can see a lot of data on the Internet and I will summarize it myself, 1. Compare the two time values (or strings to indicate the time) Select * from table where to_date (Field 1, 'yyyy-mm-dd hh24: mi: ss')> =

Select a. *, rank () over (order by cj desc) pmFrom ((Select 'A' name, 1 cjFrom dual) Union (Select 'B' name, 1 cjFrom dual) Union (Select 'C' name, 2 cjFrom dual) Union (Select 'D' name, 3 cjFrom dual) Union (Select 'E' name, 3 cjFrom dual) Union

Description:This article only provides a brief introduction to installation, without detailed instructions on installation. It solves problems encountered during oracle installation,It is no longer depressing for kids who are in touch with oracle in

1. Create a logical directory. This command does not create a real directory in the operating system. It is best to create a directory as an administrator such as system.Create directory dpdata as '/opt ';2. Check the Administrator directory (check

1. Set the environment variable NLS_LANG  To solve the Oracle client garbled problem, the key is to unify the character set used by the server with the character set used by the client.  The Oracle client (Sqlplus, OCI, etc.) uses the NLS_LANG

Recently I installed Oracle 11g, which consumes a lot of performance. The service station has over 500 mb of memory, and the CPU is also high. You can close the service when you are normal. Open it when you are using it. Disable the service

1. About PL/SQLStands for "Procedural Language extension to SQL"Is Oracle Corporation's standard data access language for relational databasesProdides a block structure for executable units of code2. PL/SQL Block StructureDECLARE

After starting sqlplus each time, you need to make some basic settings before editing the code. Today, let's take a look at the book and find a simple way to solve it. Find the login. SQL (glogin. SQL) file in the oracle installation directory. My

1. Import and export Oracle databasesCommands and PL/SQL tools can be used for import and export. 1. Command MethodDatabase Export:1) completely export the database TEST. The username "system Password manager" is exported to "D: \ daochu. dmp". exp

Oracle view users, user permissions, user tablespaces, user default tablespaces 1. view the relationship between users and default tablespaces. Select username, default_tablespace from dba_users; 2. view the table of the current user: select

-- 3. extract the current row of the cursor and store it in the variable fetch cur_stu into v_stuno, v_stuname; loop if cur_stu % found then -- if the cursor cur_stu points to a data row, print the result dbms_output.PUT_LINE (v_stuno | '->' |

The difference between the Oracle database and the MySQL database is what we will introduce in this article, hoping to help you. 1. group function usage rules: Group functions in mysql can be used at will in select statements. However, if a group

　　The period-over-period ratio is the nth month of the year and the nth month of the year, or the nth month of the year. Create a test table. Assume It is a sales quantity table: create table t (dt date, cnt number). insert some test data as needed.