Oracle

--view disk statements that consume the most disk read and write rates Select * from(SelectV.sql_id,v.child_number,v.sql_text,v.elapsed_time,v.cpu_time,v.disk_reads,rank () Over(Order byV.disk_readsdesc) Elapsed_rank fromV$sql v) awhereElapsed_rank

1 SelectA.accountcodeid, A.accountcode, A.accountcodename,2Sys_connect_by_path (A.accountcodename,'\') asFullName, A.parentcodeid, Level3 fromFm_accountcode a4 whereA.accountcodeid>= 100005Start withA.parentcodeid is NULL6Connect byPrior

For exampleFirst, create a, b two tables, in order to facilitate understanding, both tables create only one field column, respectively, A_col and B_col, add a tableData 1, 4, 5, 9, add B table Data 2, 3, 4, 5.Second, enter the following statement:

Partitioned tables in Oracle are frequently used in systems that are more frequent in systems with large amounts of data.When you refer to a partitioned table, you must first understand what a partition is. In fact, the so-called partition is simply

Oracle DB allows external tables to be queried in read-only form. The external table can be stored in any storage device that can be read by Oracle DB, its contents are not saved in db, the DB only saves external table metadata,db can query (join,

Oracle installation: Merging two files Global Users: AchievecPassword: Admin123456Users: ScottPassword: TigerOracle Development tools: SQLPLUSW and sqlplus and PL/SQL developer Oracle directives: Conn[ect]

Oracle uses JDBC for additional pruning checksDatabases and tablesTableUSERS(USERNAMEVARCHAR2(20)  not null,   PASSWORD  varchar2 20) ) altertable users   add constraint  u_pk primary  key  (USERNAME) /*** Jdbcexample.java**

1. ClassificationSeveral types of log files in Oracle Redo log files–> Online redo log Archive Log files–> Archive logs Alert Log files–> Alarm logs Trace files–> trace log User_dump_dest–> User trace log

Create a dictionary-managed tablespacecreate tablespace james datafile ‘/opt/oradata/orcl/james01.dbf‘ size 50 M, ‘/opt/oradata/orcl/james02.dbf‘ size 50 M minimum extent 50k extent management dictionary default storage (initial

InstallationFor installation Environment Select 2008R2, Memory 2G or more. Install path Select Plain English path.Installing the ServerInstall ClientInstall additional development tools (PL/SQL)UnloadingTurn off the appropriate service (restart

Introduction to LONGRAWBLOBCLOB type in Oracle Note: RAW: unprocessed type, which can store binary data or byte charactersLONG: variable-length string data. The maximum length is 2 GB. LONG has the VARCHAR2 column feature. It can store at most one

Oracle (iii) -- other database objects (Summary Series)Opening section ·_·In addition to views, other database objects include sequences, synonyms, and indexes. The most important part is the sequence (associated with the trigger). synonyms and

How to grant users the permission to view Stored Procedure definitions and stored procedure Permissions A user asked me how to grant a user the permission to view the definition of certain stored procedures, rather than letting the user modify or

Oracle recursive query and Oracle recursive query 1 select. accountcodeid,. accountcode,. accountcodename, 2 SYS_CONNECT_BY_PATH (. accountcodename, '\') as fullname,. parentcodeid, level 3 from fm_accountcode a 4 where. accountcodeid> = 10000 5

The instance explains how to handle 80 million data records temporarily and how to handle 80 million data records. Recently, When I deduplicate a million data business table, the de-duplication operation was stuck. The following is a simple review. 1

The efficiency of exists and not exists usage in and exists statements in oracle. oracleexists Blog source (exists and not exists usage in oracle): http://chenshuai365-163-com.iteye.com/blog/1003247 Blog source (the efficiency of in and exists

Oracle uses parallel pitfalls How can we quickly delete tens of millions of data records from tables with 10 million data records? You cannot directly delete the file. The best method is: 1. Use create table 2. Concurrent primary key and index

Database selection of different service logic Constraints I think the constraints on data tables are still very useful. At least there are many database optimizations, which can greatly improve the retrieval efficiency and play a significant role,

Use ORACLE online redefinition to change a common table to a partitioned table1. First create a test table and insert the test data: create table myPartition(id number,code varchar2(5),identifier varchar2(20));insert into myPartition values(1,'01','0

PartitioningTechnologies supported by Oracledatabase and RACdatabase) Partitioning Technologies supported by Oracle database and RAC database) For the original article, see the following