Oracle

In actual development applications, Oracle databases are often heard about creating a database, creating an instance, and starting an instance. Ask them what a database is and what an instance is. They probably give the answer that the database is

In Oracle, writing stored procedures using PL/SQL is a common method. I often encounter file read/write problems. Oracle PL/SQL can perform read/write, add, delete, and other operations on system files. Here is my practice. First, you need to add

There is a demand that looks very simple, but I also checked a lot of information and recorded it. The requirement is as follows: Use a trigger to modify other fields based on some modified fields in a table. ExampleCodeAs follows:     /*

Oracle provides wrap tools for encrypting procedure, function, and package.Source code.However, the encryptedCodeThe decryption fails. Keep the source code safe!Example: 1. Set Environment VariablesAddNls_lang = "simplified chinese_china". zhs16gbk

Source code: Declare Cursor C1 Is Select * From Src_list For   Update   Of Callednum,Businessnum,Startdate,Starttime,Duration,Unitnumber,Break;V_callednum Varchar2 ( 20 );V_startdate Char ( 8

In Oracle SQL PLUS, after the update, delete, or select DML operations, the number of rows updated, deleted, or retrieved is displayed. In the JDBC operation, the returned value also indicates how many rows are affected. But how can we obtain this

In archive log mode, there may be an annoying ORA-00257 error when the size of the archive log exceeds the maximum, as we have discussed how to increase the archive log space. In a common development environment, there is no need to archive logs. At

Oracle does not have the date () function. The sysdate function value includes the time, minute, and second. It is really troublesome to insert the default value of the current time. You have to write the stored procedure on your own, and you cannot

Select a row of records in the Table: (understanding: rownum is the number of rows sequentially allocated from the query returned by the Oracle System)Select * from (select rownum A, T. * From testtab t) where a = 2;Select * from (select rownum A, T.

Posted on Xu jianxiang   1. Execute the exp command to export the DMP File Migrate some tablesExp username/password @ db_name tables = (Table1, table2) file = filepath. dmpMigrate a database under a userExp username/password @ db_name owner = (user1

Connection between J2EE applications and Oracle databases Author: Hong Jian In J2EE application development, establishing a connection between an application and a database is a common problem. Here I will talk about connecting to the Oracle

1. Create a table T2 with the structure of table T1 Create Table T2 as select * from T1 where 1 <> 2; 2. Create a table T2 with the structure and data of table T1Create Table T2 as select * from T1; 3. Modify Michael user to save the tablespace as

Common commands in oracleChapter 1: Log Management 1. forcing log switchesSQL> alter system switch logfile; 2. forcing checkpointsSQL> alter system checkpoint; 3. adding online redo log groupsSQL> alter database add logfile [group 4]SQL>

I. entity integrity in OracleOracle provides the primary key clause in the create table statement, which allows you to specify the primary key column of the link when creating a table. For example, in the student-Course Selection database, you can

Version: 10.1 Sample Database: ORCL mode: hr Understanding of window function:The Window Function specifies the size of the data window used by the analysis function. The size of the data window may change with the change of rows. For example:Order

Port Number Description 1521 Default port of TNS Listener 1522-1540 Port used by TNS Listener 1575 Default port of Oracle Names Server 1630 Default port for Oracle Connection Manager-client

Create sequence command PURPOSE: To create a sequence. A sequence is a database object from which Multiple users may generate unique integers. You can use sequences To automatically generate primary key values. SYNTAX: Create sequence [schema.]

The term "Myth" refers to the basic situation of Oracle's behaviors that have never been true or have been true, but are not true. The root cause of most Oracle mythology is the result of a technology change. Most people think that many of today's

Let's take a look at the output information of lsnrctl status: Services Summary...Service "PLSExtProc" has 1 instance (s ).Instance "PLSExtProc", status UNKNOWN, has 1 handler (s) for thisService...Service "catadb" has 2 instance (s ).Instance

3. Introduction to lag and lead functions Select area_code, bill_month, local_fare cur_local_fare,Lag (local_fare, 2, 0) over (partition by area_code order by bill_month) pre_local_fare,Lag (local_fare, 1, 0) over (partition by area_code order by