Oracle

Drop deletes the entire table's datasheet structure. Transaction cannot be rolled back.? 1 drop table test; Truncate deletes all the data in the table and does not line up. And the transaction cannot be rolled back.?

The following is a detailed analysis of the wording of the IF statement in Oracle Pl/sql, the need for a friend to come over the reference to the following copy code code: /*If statement:Determine the number entered by the user.*/Set Serveroutput

The first point to note is that the ORA-01555 error is a "safe" error that does not result in data loss or corruption, but that the query that received the error cannot continue. The following is the reason for the occurrence of ORA-01555 errors are

After a large number of deletions to the table, there may be a lot of free space can be recycled, the relevant calculation methods refer to the following: UPDATE STATISTICS Analyze table compute Statistics; Calculate Fragmentation Space SELECT

Database security problem has been one of the focus of attention, we know that a business or organization of the database if the hacker attacks, and these databases and the preservation of very important data, such as banks, communications and other

When using Sqlplus to connect to Oracle databases, there are always???? A class of characters, mainly because the server and client language settings are not the same. In the Japanese environment, the server-side setting is Ja16sjis, the client

1. Start-> Settings-> Control Panel-> Management Tools-> ServicesStop all Oracle Services.2. Start-> Program->oracle-orahome81->oracle installation products->Universal InstallerUninstall all Oracle products, but universal installer cannot be deleted

--Create a new temporary log file ALTER DATABASE add logfile Group 4 ('/u01/app/oracle/oradata/orcl/redo04.log ') size 10m; ALTER DATABASE Add logfile Group 5 ('/u01/app/oracle/oradata/orcl/redo05.log ') size 10m; ALTER DATABASE Add logfile Group

Linux host 16g memory, modifying Oracle database memory parameters:1, edit/etc/fstab file: For TMPFS line defaults change to defaults,size=12g (pay attention to the format, can not appear error) After modifying the contributing memory parameters,

In my opinion, the view of Oracle is used to map the results of the associated query of multiple tables into a "temporary table", and the view is in real time corresponding to the data in the system tables.We can manipulate a view query just like a

This article mainly introduces the use of RowNum and Row_number () in Oracle, as well as the differences and links, very detailed, the need for small partners can refer to.Row_number () over (partition by col1 ORDER by col2) indicates that,

One, ALTER TABLE name modify field type (word length);If not, use the second method:Two--Create tablecreate table TABLE1 ( col1 Number (9), col2 char (20));//attempt to modify ALTER TABLE TABLE1 MODIFY COL1 Number (10 ); --Modification succeeds

1. Use dual with Connect by levelCreate Table as Select as ID from by Level100000;However, there is a limit of connect by level, if exceeding the limit, the system will report, "Connect by Level" Memory is not enough, I tried 10 billion data can,

#useradd oracle-g oinstall-g dbaCreate a new Oracle user, which initially belongs to the Oinstall group (the base group) and also to the DBA Group (additional group).-G: Specifies the starting group to which the user belongs.-G: Specifies the

Interview these days, (during the interview, did not prepare anything, because recently very tired, brought a body past, basically did not take the brain)Well, we're pretty much on the technical side.Let me ask you one more question.A transaction in

--5 constraints, PRIMARY KEY constraints, FOREIGN KEY constraints, UNIQUE constraints, check constraints, non-null constraints.--Add PRIMARY KEY constraint Alter table table_name add constraints Constraint_name Primary key (column_name);--Syntax

1. Change the Chinese folder name to English (use Administrator account, enter the system, after the change, log back to the previous account)A. Enter the "C: \ User" directory to replace "Deng Yi" with "username"B.regeditHKEY_LOCAL_MACHINE\SOFTWARE\

EF Codefirst with ORACLEResolving stored procedures has not found a solutionSo there was no way to use the most basic solution.Using the ADO basic Access class provided by oracle.manageddataaccess, you do not need to refer to the third-party class

When a case is used primarily to give data to a value that is understandable,--Simple Case functionCase SexWhen ' 1 ' Then ' men 'When ' 2 ' then ' women 'Else ' other ' END--case search functionCaseWhen sex = ' 1 ' Then ' man 'When sex = ' 2 ' Then

First, CREATE TABLE tbl_test(ID number,NAME VARCHAR2 (+),PID number DEFAULT 0)INSERT into Tbl_test (id,name,pid) VALUES (' 1 ', ' 10 ', ' 0 ');INSERT into Tbl_test (id,name,pid) VALUES (' 2 ', ' 11 ', ' 1 ');INSERT into Tbl_test (id,name,pid) VALUES