Oracle

Ii. Transactions and LocksWhen performing transactional operations (DML statements), Oracle locks the table on which it is acting, preventing other users from modifying the structure of the table. This is very important for our users.III. Submission

Connect to: Oracle Database 11g Express Edition Release 11.2.0.2.0-64bit ProductionThe main Table "test" was successfully loaded/unloaded. " Sys_import_full_02 "Start "Test". " Sys_import_full_02 ": test/******** directory=dpdir dumpfile=test_14.dmp

use of the EXP and IMP commands of Oracle We usually import and export Oracle data, and before Expdb,impdb (10G), we use exp export, IMP command to implement the import. Open the cmd window, implement IMP,EXP is mainly SQLPLUS.EXE

Follow the steps below:1, check the user's proifle is which, is generally default:SQL>SELECT from Dba_users;2. View the password expiration settings for the specified profile (such as default):SQL > SELECT * from WHERE S.profile='DEFAULT' and

--Create a functionCreate or Replace function Add_sal (ssal number) return numberIsBegin if (Ssal >) Then return ssal + 51; elsif (Ssal >) Then return ssal + 111; Else return ssal + 222; End If;EndSelect Sal, Add_sal (SAL) from

--Query The SQL statement being executedSELECT osuser Computer Login status,program that initiated the request,USERNAME user name of the login system,SCHEMANAME,B.cpu_time spends Cpu time,STATUS,B.sql_text Execution of SQL,B.From V$session ALeft

Oracle of the DatabaseI. Management of the user1. The user is like a person in the company, and the authority is what the person can do in the company, his role is to explain his position.2. The user's privileges are divided into:System permissions:

Take student table as an example to page out pure SQL pagingSELECT * FROM (SELECT- rownum,a.* from- STUDENT ORDER by Createtime DESC ) A WHERE ROWNUM &L t;=) WHERE ROWNUM >=1;MyBatis Sub-page select * FROM (select a.*,rownum

㈠ unreasonable large table full table scanSee: Click to open linkV$session_longops View records all SQL statements for more than 6 secondsMost of this is the full table scan statement!㈡ statement sharing is not goodOften haunted in OLTP, because the

Recently, the company leaders told the next product, may be related to Oracle database, previously used most of the MSSQL, the previous time to learn MySQL is a little used. Oracle has no contact. Should be for me to have done before. NET

1. When querying a table when there are multiple indexes in the where condition, the primary key index is preferred, and the other indexes are invalidated.2, when the data returned by the query as a percentage of the total data is less than 20%, the

1. Site test version, need to back up local data, import to the server. Table space and several users were created on the server. Now delete the useless user(1) Query out all the users and the corresponding tablespace: select

These issues can be addressed in different ways in the Oracle database due to version differences.There are several ways to implement such a feature:1. Modify the Sqlnet.ora file to restrict access to the IP of the database.2, the use of trigger

How Oracle implements a one-stop operation for creating databases, backing up databases, and importing data exportsThe management of data objects and data in Oracle is undoubtedly managed using PL/SQL developer, which also provides us with a lot of

First of all, I think most people define a database as a collection of data that is called a database. In Chinese translation we usually make a library of what is called somewhere in the store. and storing a lot of data together is called a database,

1. Get system time, current timeSelect sysdate from dual2. Date functionWhen using date calculations in SQL statements, you must use a Date function to convert the string to a date type, unlike using a string directly in SQL Server.to_date ("string",

As a rookie, after completing the installation of the Oracle database, you do not know how to start. After some toss and then understand some of the reasons, summed up as follows:In fact, the Oracle database and MySQL database start are the same

Oracle is the first step in database learning: database installation, and oracle 1. Local oracle Server 1. to install the oracle server, you can download the server that matches your computer on the official oracle website. Generally, the server

Query, disable, enable, and delete Foreign keys in Oracle 1. query the Foreign keys of all tables:   select table_name, constraint_name from user_constraints where constraint_type = 'R'; 2. Disable all foreign key constraints and use the following

Solution to Oracle Scott lack of view permissions, oraclescott In PL/SQL Developer database management tools, log on with the SCOTT user account, create an SQL query window, enter an SQL statement to create a view, and then an error message is