Oracle

Six errors and solutions that Oracle beginners often encounter:1. ORA-12541: TNS: No listenerCause: the listener is not started or damaged. For the former, run the net start OracleOraHome81TNSListener command (the name may be different). For the

Today, I made a serious mistake at work: I got rid of the data in the Oracle database used by our system! When I found myself correct, I suddenly burst into a cold sweat. However, if we do not back up the database on a regular basis and recover the

SQL> select to_char (sysdate, 'yyyy-mm-dd') from dual;SQL> select to_char (sysdate, 'hh24-mi-ss') from dual;Mysql> select date_format (now (), '% Y-% m-% D ');Mysql> select time_format (now (), '% H-% I-% s '); Date Functions Add a month:SQL> select

The functions mentioned in this article are not all functions of Oracle and SQL Server. Especially the analysis and mining functions are not fully covered. Please give priority to solving the problem in practice.1. Absolute ValueS: select abs (-1)

DocumentIn a project, you may often encounter operations on several databases in a project. If the database type is the same, you can directly connect two databases or use the database synchronization function. If our project uses SQLServer2005 for

View all tables in Oracle:Select * from tab/dba_tables/dba_objects/cat;View the table created by the user:Select table_name from user_tables; // The table of the current userSelect table_name from all_tables; // tables of all usersSelect table_name

Fully uninstall oracle9i in windows Delete Registry HKEY_LOCAL_MACHINE \ SOFTWARE \ ORACLE Delete oracle service All Services under HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ ORACLE Delete Event Logs HKEY_LOCAL_MACHINE \

This article introduces the import and export of Oracle Data imp and exp commands, and describes the corresponding parameters. Drills to deepen understanding.At last, the article discusses the problems that may occur when using these two commands

Expdp oracle exports the backup and deletes the backup seven days ago. The backup is retained on the first day of each month and every Monday. Use oracle expdp to export the database and delete the backup from the past seven days. However, the

1. Shut down the database[Oracle @ RHEL5] $ sqlplus/as sysdbaSQL> shutdown immediate;Ii. Disable listening[Oracle @ RHEL5] $ lsnrctl stop3. Delete oracle_baseI switched to root here.[Root @ RHEL5] # rm-rf/s013. Clear residual files[Root @ RHEL5] #

After finishing the project yesterday, I asked the test to test it. The test said that paging query does not seem to work. After Turning to page 4th, the data results will be the same.At that time, I was puzzled. It was impossible. The paging

1) create a storage directoryMkdir backup2) Write a shell script #! /Bin/bashExport ORACLE_BASE =/opt/oracle -- the path must be changed according to the actual path.Export ORACLE_HOME = $ ORACLE_BASE/ora10gr2/db_1 -- the path must be changed

1. The case when expression has two forms:Copy codeThe Code is as follows:-- Simple Case FunctionCASE sexWHEN '1' THEN 'male'WHEN '2' THEN 'female'ELSE 'others' END-- Case search functionCASEWHEN sex = '1' THEN 'male'WHEN sex = '2' THEN 'female'ELSE

SQL1:Copy codeThe Code is as follows:-- 1. view the table space name and size.SELECT t. tablespace_name, round (SUM (bytes/(1024*1024), 0) ts_sizeFROM dba_tablespaces t, dba_data_files dWHERE t. tablespace_name = d. tablespace_nameGroup by t.

In principle, the Recycle Bin is a data dictionary table that stores information about database objects deleted by users. Objects deleted by a user are not deleted by the database and still occupy space. Unless the user Purge manually or the

Content • Software environment• A simple demonstration of Row-level locks caused by concurrent Oracle databasesThis article briefly demonstrates the row-level locks caused by concurrent Table Primary keys. More than two concurrent users modify the

I recently used oracle rownum for paging display, and made further analysis and research on rownum. This is summarized as follows, hoping to benefit everyone.For rownum, it is the number of the row returned from the query that is sequentially

The following error is always reported when you manually configure the EM of Oracle11g:WARNING: ORA-00001: uniqueconstraint (SYSMAN. PARAMETERS_PRIMARY_KEY) violatedORA-06512: at "SYSMAN. EMD_LOADER", line4986ORA-06512: atline1.No solution was found

Mathematical functions1. Absolute ValueS: select abs (-1) valueO: select abs (-1) value from dual2. INTEGER (large)S: select ceiling (-1.001) valueO: select ceil (-1.001) value from dual3. Round (small)S: select floor (-1.001) valueO: select floor (-

I believe that three appropriate indexes should be created, that is, the appropriate number of indexes should be created on the appropriate tables and columns. Although this can be summarized in one sentence, the database administrator must make