Oracle

% Rowtype in Oracle:   % Rowtype: indicates that this type is the row data type. It is stored as a row of data. A row has many columns, which is equivalent to a row of data in the table or a row of data in the cursor.   % Rowtype is used to

1. Find the MOST Group   Select XX. qssj from (select cm. persionid, CM. qssj, row_number () over (partition by cm. persionid order by cm. scrq DESC) as RnFrom rs_rsk_contract_manage cm where cm. bak_flag is null) xxWhere XX. persionid = A. ID and

Generally, you can use break on column skip XX to sort the query results. The parameters of the break on command are as follows:Clear breaks clear all break DefinitionsBreak on column is interrupted on this columnBreak on row is interrupted on each

Windows Oracle connection error ORA-12560: TNS: protocol adapter Error There are three reasons for the problem that caused the ORA-12560: TNS: protocol adapter error: 1. the listening service is not up. For Windows, perform the following

Oracle select for updateIn most cases, the rows checked by the cursor are modified for the processing completed in the extraction loop. PL/SQL provides a syntax for such processing. This syntax includes two parts: the for update clause in the

Differences between nvarchar2 and varchar2 in Oracle[Convert] the difference between nvarchar2 and varchar2 is that nvarchar2 is related to character sets during length calculation. For example, if the database is a Chinese Character Set and the

Top-level users: Username: SYS Link: sysdba Role creation: /* Create the Customs V2.0 configuration library */drop tablespace cms_para including contents and datafiles; Create tablespace cms_para logging datafile 'd: \ oracle \ oradata \ orcl \

-- Monitor whether the index is usedAlter index & index_name monitoring usage;Alter index & index_name nomonitoring usage;Select * from V $ object_usage where index_name = & index_name; -- Calculate the I/O distribution of data filesSelect DF. Name,

1. Describe the relationship between tablespace and datafile Tablespace is a logical component of the database. Physically, the database data is stored in the data file. Logically, the database is stored in the tablespace, which is composed of one

It was originally with images. when the results were saved, too many images were lost (Crying fast) Download Li Xinghua Oracle video notes: Click to open the link I'm using Windows 64-bit, Oracle 10:

Link: http://user2005.blog.163.com/blog/static/137589500201123141041319/ PrefaceThe Oracle distributed database system is a customer/server architecture. Its structure is 1. In a network environment, each hardware platform with multi-user processing

Use of sequences in Oracle Oracle provides a sequence object that is provided by the system for auto-incrementing serial numbers. It is usually used to generate auto-incrementing primary keys or serial numbers for database data records. The

　 1. Physical Structure (composed of control files, data files, redo log files, parameter files, archive files, and password files)　　 The data in a database is stored in physical files on the disk. When used, the data is transferred to the memory. 　　

There are several startup methods: 1. startup nomount Non-installation startup. In this mode, you can execute: re-build the control file and re-build the database. Read the init. ora file and start the instance, that is, start the SGA and

If it is only a lock, the following statement can detect all user locks:   Select S. username,Decode (L. type, 'Tm ', 'table lock', 'tx', 'row lock', null) lock_level,O. Owner,O. object_name,O. object_type,S. Sid,S. Serial #,S. Terminal,S. machine,S.

So far, the export/import toolset is still the preferred utility for transferring data across multiple platforms with the minimum labor intensity, although it is often complained that it is too slow. Import only reads each record from the export

The Oracle database provides several different methods for starting and disabling databases. This article describes the differences between these methods and their respective functions.1. For most Oracle DBAs, the most common method to start and

This error occurs when you create a database instance while installing Oracle 11g R2, And if you select ignore, A ora-28000 error occurs. After network query and verification, this is a password starting with a number when the administrator password

I. Databases A database is a collection of data, while Oracle is a software system that manages these data sets. It is an object-relational database management system. Ii. tablespace The tablespace is the logical ing of Oracle to the data in the

Single-row functions are mainly divided into five types: The varchar2 function, the number function, and the date function, Common functions, Conversion functions Character FunctionsThe main function is to operate string data, such:. Upper (string