Oracle

 Today, I am discussing the index understanding in a Java group and other people.I have never understood what they are talking about for a long time.I also checked a lot of index definitions on the Internet,However, there are no specific examples

How to efficiently Delete duplicate data in Oracle: 10:18:43 Source: Network Author: Unknown CLICK: 39 deduplication technology can provide a larger backup capacity for longer data retention, it can also achieve continuous verification of backup

When writing the SQL statement for creating an oracle table, the statement for dropping the table is usually added before "CREATE" for SQL Execution. However, the statement for dropping the table before "CREATE" is executed for the first time, an

1. UUID is a 32-Bit String, so the size of the database primary key field must be greater than or equal to 32 characters. In addition, if a trigger and sequence are set in the database table, even if the uuid primary key generation policy is used,

From my own blog. Recently I am studying Oracle and need to use the Oracle sample database. I have installed Oracle 11g R2, and there is no sample database after installation. You need to download the Oracle examples package from the Oracle

Because I have poor memory, I often cannot remember the commands. Note that it is not very bad, it is too bad, and it is also relatively lazy, so I want to write a little thing and release the labor force. so I had an idea to write a small tool for

Recently, I encountered this problem when using spring 2.0 + hibernate 3.1 + myeclipse6.5 to integrate development projects. The exception is as follows:    It is very big, and when hibernate ing is used to reverse, this error will also be reported,

// Create a spatial field index for Oracle Spatial table// ================================================Drop index index_sp_v_gbjj;Drop index index_sp_v_xzq;Drop index index_sp_v_ytfq;Drop index index_sp_v_dltb;Drop index

SQL database Oracle Database Isnull (field name, replace value) ------------------------------------------------------------- nvl (field name, replace value) Substring (field name, start position, cut length) ---------------------------------------

When using MySQL, you often need to replace the field with a null value. It is not feasible to directly use "field name = NULL". The correct method is:Where isnull (field) in )" Syntax: Replacement of a null value found in ms SQL Oracle MySQL In

Chapter 2 DML and transaction control-v512 workshop Editor: Xuan Yu Merge Save point   My blog Update Transaction Control V512 Studio Delete Automatic submission of sqlplus Chinese Emy of Sciences

This is the note I made when I learned Java by myself. Some of them are too long and some are not fully described. Some explanatory texts are very important, especially for beginners who are new to Java. Even now, I still think these explanations

There are two ways for a database to access image information: 1) convert to binary data storage, so first set the Data Type of the corresponding data field to blob. 2) The server sets the path to save the uploaded file. Only the file path is stored

Using system; Using system. Collections. Generic; Using system. text; Using system. Data. oracleclient; Using system. Data; Namespace oracleopdemo { Class Program { Private Static string connstr = "Data Source = oratest; user id = m;

The database has a worker table with the following content: SQL> select * from worker; Employee number name gender Date of Birth Party member does not participate in work department number------------------------------------------------------------1

Lock concept Basics A database is a shared resource used by multiple users. When multiple users access data concurrently, multiple transactions can access the same data simultaneously in the database. If concurrent operations are not controlled,

Today, with the help of the instance for configuring Oracle database connection, we will learn one way to read XML files (other reading methods will be introduced later)-using dom4j + XPath. Dom4j is an open-source XML parsing package produced by

1. Define the primary key as the automatic growth identifier type In MySQL, if the table's primary key is set to auto_increment type, the database automatically assigns a value to the primary key. For example: Create Table MERs (ID int

Oracle Database development (1). Configure proc in Windows 20070606 Papayas I. Summary Proc is a development interface provided by Oracle database and supports multiple languages. Although proc debugging and maintenance are inconvenient,However, the

It has been plagued by the Unicode problem of Oracle 9i nvarchar for a long time. On the Internet, I can see an article KB-Oracle 9i nvarchar Survival Guide.To solve this problem in C #, I want to know how to solve it in Delphi 2009 (Delphi 2009 now