Oracle

Oracle Query table information (indexes, foreign keys, columns, etc.)Oracle query table information, including table name, field name, field type, primary key, FOREIGN key Uniqueness constraint information, index information query SQL as follows, we

First, SQL ServerAdvantages:Ease of use, scalability for distributed organizations, data warehousing for decision support, integration with many other server software, and good price/performance ratio;Provides flexibility for data management and

1. Define the primary key as the auto-grow identifier typeMysqlIn MySQL, if the primary key of the table is set to the auto_increment type, the database is automatically assigned a value for the primary key. For example: Customers (ID auto_increment,

A few days before the installation of the Oracle test environment, found today cannot use local IP connection, connection prompt error "Oracle The network adapter could not establish the connection" This problem toss me a long time, online a lot of

"Deep analysis--eygle" study notes1.2.3 PGA Management:[Email protected] Sql>show parameter area_size NAME TYPE VALUE---------------------------------------------------------- ------------------------

1. Returns the decimal number corresponding to the specified characterSelect ASCII (' A ') a,ascii (' Z ') a,ascii (' 12 ') a dozen, ASCII (') kg from dual;2. Returns the character corresponding to the specified decimalSelect Chr (A,CHR) (122) z

Today to build the library, the use of the OMF method, the results of the file name using Oracle Automatic naming method, do not understand Ah, so decided to delete and rebuild.Oracle provides instructions for deleting a database:DROP

The most common way to merge column values is to write a custom function to the fact that this is the other way around.The merge column values in SQL Server can use the for Xml Path, which in Oracle can use Wm_concat or Listagg.Prepare the

MS SQL to Oracle Data Migration noteI. Background of the taskThe old system uses the MS SQL Server database, the new system uses the Oracle database, and now the data from the old system needs to be migrated to the new system, and the old data can

Create or Replace function Func_chinese(P_str in VARCHAR2,--input stringP_code in Varchar2,--Dump (String)P_chinese in Pls_integer--1, extracting Chinese characters, not 1, extracting non-Chinese characters) return VARCHAR2AsV_code varchar2 (32767):

Many services are installed when you install Oracle 9i under the Windows operating system--and some of them are configured to start when Windows starts. When Oracle runs under Windows, it consumes a lot of resources, and some services may not always

advantages and costs of using indexes. Advantages: 1 The index is a conceptual part of the table used to improve the efficiency of retrieving data, and Oracle uses a complex self-balancing b-tree structure. In general, querying data through an

Query and delete of Oracle's next session1. Query the current sessionsql> Select username,sid,serial# from v$session where username are not null; USERNAME SID serial#------------------------------ ---------- ----------SYS 144 4HYL 146SCOTT 147HR 159-

Blocking is a common scenario for DBAs, especially poor application design blocking that can cause severe performance degradation until the database crashes. For DBAs, it is necessary to know how to navigate to what is blocking the current system,

Background: My own machine to do Oracle server, the other machine can ping my machine, but JDBC is not even, and later with Plsql even appear no listening program ....After I reinstalled Oracle yesterday, there was a ora-12541:tns when connecting to

(Transferred from: http://blog.csdn.net/marshalchen/article/details/6552103)SELECT * from User_tab_cols where column_name=upper (' xxxxx '); query which tables have a columnSelect status from User_objects where Object_name=upper ('

First, the database nameWhat is a database name? The database name is the identity of a database, just like a person's ID number. He uses parameter db_name to indicate that if a machine is loaded with multiple databases, then each database has a

Before giving you a specific introduction to Oracle Hints, let us first understand what Oracle Hints is and then fully introduce Oracle Hints, which I hope will be useful to you. The cost-based optimizer is very smart, and in most cases it chooses

Implementation of oracle column merge: oracle column merge In many cases, we will use oracle column merge. oracle provides the following methods to implement column merge: 1. Before Oracle 10 Gb, WMSYS. WM_CONCAT was used: Wmsys. wm_concat separates

Oracle Database Connection error: ORA-01034: ORACLE not available (Oracle does not exist), ORA-27101: shared memory realm does not exist, oracleora12505 It takes one and a half days to solve the problem that the client cannot connect to the oracle