Oracle

Tag:sql    optimization    oracle    execution Plan     database      How to limit CPU utilization? How to scan the big table most quickly. If the large table has a primary key, COUNT (*) will go to the primary key, and Oracle only needs to scan the

This article describes how to connect an Oracle database by thin1. Create Web project and copy the Ojdbc14.jar under the D:\oracle\product\10.2.0\db_1\jdbc\lib (Oracle installation directory) to the LIB path in the project Web-inf directory.2.

Today, the second configuration of PL/SQL developer, said that the egg hurts, yesterday because moved a thing and then inexplicably can not connect the database, always show a variety ofError, I moved the thing is because the Chinese will show

Oracle transaction-based temporal tables, under 11g and 12C, can be seen when statistics on temporary tables are collected, the former records are emptied, the latter is not, which is an important distinction. In the company environment with 12C, in

can be connected directly via SECURECRT or TelnetStart listening command: Lsnrctl startAfter successful boot: Sqlplus/nolog enterConn/as SYSDBA EnterStartup returnSELECT * from User_tables; EnterResults, OK start monitoring and service

1. Change non-archive mode to archive mode:1) sql> Conn/as sysdba (database connected as DBA)2) sql> shutdown immediate; (Close database now)3) Sql> startup mount (launches the instance and loads the database but does not open)4) sql> ALTER DATABASE

Continue on the article to build a DB node, DB node construction and build a common RAC no difference, it is necessary to note that the following two points:1. Create a related directory and add two files[Email protected] ~]#

When SQL Server accesses a database table in Oracle remotely:The remote syntax is typically: SELECT * from OpenQuery (Oracle linked server name, ' query statement ')Eg:select * from OPENQUERY (QTX, ' select * from student ')In some cases, only the

1. View all users in the current database: Select username from dba_users;2. View the user logged in for the current session: Show users or select username from user_users;3. View all tables for a user: SELECT * from Dba_tables where owner= '

This article mainly introduces the basic management of CDB and PDB, data source Oracle official.Basic concepts:Multitenant Environment: Multi-tenant environmentCDB (Container database): DB containerPD (Pluggable database): pluggable databasesCDB vs.

Oracle DB ArchitectureThe Oracle DB Server consists of an Oracle DB and one or more db instances. Instances are composed of memory structures and background processes. Whenever an instance is started, a shared memory area called the system Global

*********************************************** Declaration **********************************************original works, from the "Deep Blue Blog" blog, Welcome Reprint, please be sure to indicate the source when reproduced , otherwise be held

Locally vs. Dictionary Managed tablespacesorganized from :HTTP://WWW.ORAFAQ.COM/NODE/3.When Oracleallocates space to a segment (as a table or index), a group of contiguousfree blocks, called an extent, is ad Ded to the segment. Metadata

When the data volume is small, the subquery can be used to do two table association operations, but the sub-query efficiency is too low when the data volume is large (because it is a single pair)Like what:Update Person1 p1 set p1.p_name= (select

--oracle Data Block (block) with Case study tuningData Block Overview Oracle manages the storage space in a database data file (datafile) as a data block. A data block is the smallest (logical) unit of data in a database. Corresponding to the data

ORA-00904: & quot; T1 & quot;. & quot; AREA_ID & quot;: Invalid identifier 1. Error description ORA-00904: "T1". "AREA_ID": Invalid identifier 00904. 00000-"% s: invalid identifier" * Cause * Action An error occurred while listing 45 columns

4. Create oracle username tablespaces, tables, insert data, and user management tables in windows and Linux Log on to the super administrator and run the following command: Create databases, tablespaces, users, and insert data in

Create Table space instance analysis in oracle and create instance analysis in oracle How to create an oracle tablespace? 1. If you open it in PL/SQL or other tools, directly modify the [italic bold part] in the following code to execute 2. Make

Oracle Data Pump (Data Dump) Error collection, Volume ledump Oracle Data Pump (Data Dump) often encounters some strange error cases during use. The following summarizes some problems encountered during the use of Data pump (Data Dump) and their

Oracle Development Series (1) maddening null values and null values (no results) Recently, I encountered some problems when I was doing development and writing operations. I found the cause for a long time and did not know it before. In this case,