Oracle

Dual is a virtual table used to form the select syntax rule. Oracle ensures that there will always be only one record in dual. We can use it to do a lot of things, as shown below: 1. view the current user. You can execute the following statement in

Use RMAN to back up... the command contains... crontab, which you should have. -- Archive is returned once every week ,? The archiving process automatically keeps running.-- Archive if it is full, right? What you need to do is to back up the data

In PL/SQL tools, you need to change the value of a field in a line: Method 1. Repeat the table to edit the data. In this way, you can see the data you want to change at a glance when the data volume is small. However, the update statement is

 No, too many builds will affect performance, and the maintenance cost will be high. Generally, it is created on the keyword field. For example, there are many fields after where, including the logtime field. You can create an index on this

-- View database lock details select. sid, B. serial #, B. username, B. osuser, B. machine, B. program, C. object_name, D. spid, decode (. type, 'Mr ', 'Media recovery', 'rt ', 'redo thread', 'UN', 'user name', 'tx ', 'Transaction ', 'Tm ', 'dml',

Oracle Database Instant Client 11g 11.2.0.3.0 Instant Client is a lightweight database client released by Oracle (R). You can use it to run OCI, occi, Pro * C, ODBC, and JDBC without installing a standard client.Program.Applicable to users who

Oracle connections can be divided into two types: 1. dedicated server connection structure (dedicated server ): In this way, for each user, its database application is run by the user process, and there isDedicated server processRun the Oracle

 Exec pro_create ('lt _ oa_sms ', 'smsid '); First, perform the first step: Create sequence auto_add -- sequence name (auto_add is a series name, just name it)Increment by 1 -- increase by 1 each timeStart with 1 -- start from 1Nomaxvalue -- no

1. What are the partition tables (indexes )?A partition table is a kind of data storage mechanism. It stores the data of a table in different memory segments, these different storage partitions are partitions ). Why? One of the reasons is that when

1. Introduction to Oracle Logical StructureThe logical structure of Oracle includes tablespaces, segments, data blocks, and schema objects ).Oracle databases are logically composed of multiple tables. objects stored in tablespaces are called

Happy Life of the Old Wang family     Abstraction of Oracle's Structure System An avid photographer-happy family of Old Wang     The first chapter of each Oracle book generally introduces the structure and system of Oracle. When this chapter is

 Some time ago, the Oracle Stored Procedure encountered problems. Originally written as this If 1 = 2 then NULL; Elseif 1 = 3 then Null End if; In the PL/SQL editing environment, elseif does not change color, which means it is not a

Requirements: Update the same records in Table T1 (t_statbuf) and Table T1 (t_mt) to table T1. 1. incorrect syntax: update table_name t1 set (a,b,c)=( select a,b,c from table_name_2 t2 where t1.a=t2.a); In this way, all rows in Table T1 will be

Business Needs: I created a table named t_0_mtbuf in Oracle and created it using a statement for creating a common table. In fact, this table serves as a temporary table, namely: In Java, select 1500 entries each time, insert them into the sqlserver

 Oracle uses a cursor to perform joint queries on multiple tables Declare -- defines the cursor mycur is select T. dept_id, M. station_id, M. name from person_inform T left join contacts m on T. dept_id = m. id order by T. dept_id; -- temporary

1. create function fn_ifrandom (recursion is used) Create or replace function fn_ifrandom (tmpallrandom in clob, tmprandom in varchar2, allcount in number) return varchar2is -- generate random number randomchar varchar2 (5 ); -- The final returned

Oracle provides Partitioning technology to support vldb (very large database ). The partition table judges the partition columns to store different records in different partitions. Partitions are completely transparent to applications. Oracle

This article from the Linux community website (www.linuxidc.com) original link: http://www.linuxidc.com/Linux/2010-10/29075.htm I. Permission classification:System permission: The system specifies the user's permission to use the database. (System

My questions: If you look at me, the number 1 will go through the index, and the number 4 will not go through the index to the entire table. I hope that the number 4 will go through the index, and the mandatory index statement will not work, what

For more information about what the Oracle high-speed cache is and how it works, see: Http://www.php100.com/html/webkaifa/database/oracle/2008/0709/1348.html The db_buffer_pool of Oracle consists of three