Oracle

round (X[,y])Function: Returns the value after roundingParameters: X, y, numeric expression, if Y is not an integer intercept y integer part, if y>0 is rounded to y decimal place, if Y is less than 0 rounded to the left of the decimal point.Return:

oracle10g，在pl/sql中选中删除后会出现类似：BIN$nJ5JuP9cQmqPaArFei384g==$0的表。1.查看回收站select* fromuser_recyclebin;2.清空回收站purge recyclebin;3.清空回收站中的某个表--如下方式删除会提示：SQL命令未正确结束。purge tableBIN$/UpBuh+LQ9yZGN95BFsk5Q==$0--正确写法如下：purge table"BIN$/UpBuh+LQ9yZGN95BFsk5Q==$0";

1. Ordering reasonable query conditionsOracle bottom-up analysis sequence where receipts, from the perspective of optimizing performance. It is suggested that these conditions will be able to filter out a large number of lines written where at the

㈠ Partition Table Technology Overview⑴range Partition① ExampleCREATE TABLE T（... Column Definition ... ）Partition by range (Week_num)(partition P1 values less than (4) tablespace data0,Partition P2 values less than (5) tablespace data1,....);②

The problem has occurred in the previous period:The table has a column number type rec_recordlength (two time interval length/sec)Some data statistics This field will appear "Calculate the operation Overflow" error, it is a headache, can not find

in the production environment, we will find:① Index Table Space I/O is very high② "DB file sequential read" Wait event is also higherThis indicates that the whole database system, index read and write operation is more, has become the main

Disclaimer: Although the title is Oracle, it is also suitable for MySQL InnoDB indexIn most cases, the composite index is better than the single-field indexMany systems rely on new and suitable composite indexes to increase the efficiency

Here is my mapper configuration1 InsertID= "INSERTXIANGCE"ParameterType= "XIANGCE"> usegeneratedkeys= "true" keyproperty= "paid" -2 3 SelectkeyKeyproperty= "Paid"Resulttype= "Integer"Order= "Before"StatementType= "STATEMENT"> 4 Select

Here is the description of the Oracle constraint in the OCP exam guide:The constraint types supported by the Oracle database is as follows:UNIQUENot NULLPRIMARY KEYFOREIGN KEYCHECKConstraints has names. It is good practice to specify the names with

Oracle EBS Submission Request encounters a "rogue" error today when submitting a request, encountering a request run error, status prompt "No manager". The solution is as follows: 1. Switch to system administrator responsibilities. Find the standard

There are many ways to view the SQL execution planThere are three types of methods I useSql> explain plan for2 Select * from scott.emp where ename= ' KING ';has been explained.The first of the most commonly usedSql> select * FROM table

SQL Execution procedure1. Application Layer-Application SQL request to database2. Database code layer-oracle software parsing and optimizing SQL, managing locks, security, concurrency, etc.3. Memory layer-SGA (data cache), PGA (sort and hash)4. Disk

Today the customer gave an Excel data, need and my local library data to do contrast, do not want to use the UE initialization, feel very troublesome, finally found a formula on the net slightly modified a bit to solve, memo as follows: Add a

?1. Principles of Index use?Do not use full blur on the index, but like ' asdf% ' is possible, that is, do not contains, available StartwithDo not perform functions on the index, expression operations, or use is null to determine, otherwise the full

Set the session format for date in Oracle to ' YYYY-MM-DD HH24:MI:SS 'Alter session set Nls_date_format= ' yyyy-mm-dd hh24:mi:ss ';Set the session format for timestamp in Oracle to ' YYYY-MM-DD hh24.mi.ss.ff 'Alter session set Nls_timestamp_format= '

Today, a database synchronization problem is encountered, the main library is closed, after restarting the main library, the repository does not synchronize the main library data properly. The repository can be consistent with the main library only

In Oracle, there is typically only one database on a server. In a database, different user projects are accessed by different users, each user has a database object that they create, and when a user wants to access a database object under another

Two methods:1. When creating a table, copy the data from the other tables ( and the structure of the table is also copied over ):Grammar:　CREATE TABLE table_name as SELECT column1,...... |* from Table_old;Sql>SQL> Create Tableuserinfo_new2 as 3

Example:Session 2:Sql> Connect Test/testConnected.SELECT * from V$mystat where rownum=1;143Select b.spid,a.sid,a.serial# from v$session a,v$process b where a.paddr =b.addr and a.sid = 143;?Session 1: Open the 10046 event for the corresponding

--Locate the specified snapSelectSNAP_ID,Max(sample_time) fromsys.wrh$_active_session_historyGroup bysnap_idOrder bysnap_iddesc;--AWRSELECT * from TABLE(dbms_workload_repository.awr_report_html (Selectdbid fromv$Database),1, 26663,--begin