Oracle

Method 1: Use sqlplus64-bit:[Oracle @ qs-wg-db2 ~] $ Sqlplus/as sysdba; SQL * Plus: Release 10.2.0.5.0-Productionon Sun Sep 25 08:57:22 2011 Copyright (c) 1982,201 0, Oracle. All Rights Reserved.  Connected:Oracle Database 10g Enterprise

Copy the System. Data. OralceClient. dll file to the Bin directory of the project directory, which is usually located in the C:/windows/Microsoft. NET/Franmework/v.1.1.4322 directory.// Connection stringString Oracle_ConnStr = "Data Source =

First, create profile lock_act LIMIT FAILED_LOGIN_ATTEMPTS 3 PASSWORD_LOCK_TIME 2; assign the user test profile alter user test profile LOCK_ACT;Unlock account alter user test account unlock;Create profile plt limit PASSWORD_LIFE_TIME 10

Method 1:SELECT * FROM(Select a. *, ROWNUM RNFROM (SELECT * FROM TABLE_NAME))Where rn between 3 * (3-1) + 1 AND 3*3 Method 2 paging Query format: SELECT * FROM(Select a. *, ROWNUM RNFROM (SELECT * FROM TABLE_NAME)Where rownum )Where rn> 20 *

  Permission: Create session   Create table   Unlimited tablespace   Connect   Resource   Dba   Example:   # Sqlplus/nolog   SQL> conn/as sysdba;   SQL> create user username identified by password   SQL> grant dba to username;   SQL> conn

Oracle9i introduces pga_aggregate_target to automatically adjust the PGA;Oracle10 introduces sga_target to automatically adjust SGA.Oracle11g combines these two parts and introduces memory_target to automatically adjust all the memory. This is the

  Today, a user's database suddenly finds that all clients cannot connect. However, sysdba users can log on normally;   First, it is suspected that someone has set the database to the silent mode.   Log on to the database on the server, check

Transaction isolation levelThe ANSI/iso SQL standard defines four transaction isolation levels, which are defined based on three phenomena1) dirty read (dirty read)Can read uncommitted data, that is, dirty data.2) nonrepeatable read)If a row is read

  Segments are the database objects that occupy the storage space. Each object that occupies the storage space is stored in a segment, such as tables, indexes, and rollback segments. Segment type 1) Table segment 2) table partition or

Oracle's compressed data processing is based on database blocks. In essence, it saves space by eliminating duplicate data in database blocks. The specific method is as follows: Compare all fields or records contained in data blocks, duplicate data

  A lock is a mechanism used by a database to control concurrent access to shared resources. The lock is used to protect the data being modified. Other users can update the data only after the transaction is committed or rolled back. Advantages of

  R & D colleagues said the database error during table creation: ORA-1536   [Oracle @ localhost ~] $ Oerr ora 1, 1536 01536,000 00, "space quota exceededfor tablespace '% S '" // * Cause: The space quota for the segment owner in the tablespace has /

Rowid structure analysis select rowid from dualaaaab0aabaaaaoha1_owid structure: object number file number block number xxxxxx xxx therefore, AAAAB0 object no. AAB File No. AAAAOh Block No. AAA line number how do I know the decimal encoded values of

Steps for specifying column sequence without damaging data -- T_LAW_RULE alter table T_LAW_RULE drop primary key; -- delete the primary key alter table T_LAW_RULE MODIFY (id null); -- set it to null alter table T_LAW_RULE ADD (ID_TMP CHAR (32 )); --

Test a compressed Oracle table SQL code-compress a TABLE to reduce the amount of data and reduce IO DROP TABLE t purge; CREATE TABLE t NOCOMPRESS AS SELECT rownum AS n, rpad ('', 500, mod (rownum, 15) AS pad FROM dual connect by level execute

WITH + HInt MATERIALIZE is not necessarily valid. It must be materialized after multiple calls. It is called only once, and MATERIALIZE syntax is useless: MATERIALIZE Description: indicates that the optimizer materialized the inline view-a temporary

Database optimization subtotal optimizes database tables related to XX businesses on Monday night. Cause: there are 4 tables in total, with a small data size, a minimum of 0.4 million records, a maximum of 3 million, and a size of no more than 300

Inner join, left join, where and in right join. 1. inner join (natural join): Only the rows matching the two tables can appear in the result set. 2. Outer join: including (1) left Outer Join (the table on the left is not restricted) select.

Summary of Oracle flash flashback 1. Description: The technology used. Multiple technologies are used. 1. flash Back log 2. recycle Bin 3. the rollback segment cannot use the recycle bin operation Drop table xxx purge; Drop tablespace xxx Drop user

Oracle time processing method: common date functions 1. Sysdate current date and time SQL> Select sysdate from dual; sysdate--------21- June-052. Last_day SQL> Select last_day (sysdate) from dual; LAST_DAY (s--------30- June-053. Add_months (d, n)