Oracle

1) SELECT * from T1 where exists (select 1 from T2 where t1.a=t2.a);When the T1 data volume is small and the T2 data is very large, the query efficiency of T12) SELECT * from T1 where t1.a in (select t2.a from T2);T1 data volume is very large and T2

CREATE Temporary tablespace test_tempTempfile ' C:\oracle\product\10.1.0\oradata\orcl\test_temp01.dbf 'SIZE 32MAutoextend onNEXT 32M MAXSIZE 2048MEXTENT MANAGEMENT LOCAL;Create a user table spaceCREATE tablespace Test_dataLOGGINGDataFile ' C:\ORACLE\

In Oralce, a SQL statement generates a lot of information when it executes: SQL Unique Identity SQL text Information Binding variable Information Execution plan and cursor information Statistical information Performance

First, when establishing the table, pay attention to the role of pctfree parametersPCTFREE: The percentage of space reserved for a block, indicating when the data block can be insert, the default is 10, indicating that when the free space of the

First, what is the waterline (high water Mark)?All Oracle segments (segments, where, for ease of understanding, suggest segment as a synonym for a table) have a limit on the amount of data that can be accommodated in a paragraph, we call this cap

Introduction of the Network sectionThe Oracle database server is the clientOn WindowsBuild two database Orcl with ZHS16GPK and UTFORCL Al32utf8Service ORACLESERVICEORCL and ORACLESERVICEUTFORCL OpenCmdOradim HelpLsnrctl Service1, configuration

--for the resulting UUID to conform to the RFC 4122 standard (http://tools.ietf.org/html/rfc4122), for example: A8f662b8-6e7a-13fe-e040-970a437c6bd7--functionCREATE OR REPLACEFUNCTION Get_uuidRETURN VARCHARIsGUID VARCHAR (50);BEGINGUID: = Lower

1.Oracle is the Oracle company, it should be considered a high level of the database;2. Occupation: DBA (Database administrator)3. Database classification://How to select a database: {1. Project size; 2. Cost; 3. Security}A: Small database: Access,

Beta version:System version: RHEL 6.5Oracle version: 11.2.4First, prefaceRecently in the self-taught Oracle, today try a silent installation method, nonsense not much to say below the beginning.1, prepare Oracle software, I use the 11.2.4 version,

Source Address: Http://zhidao.baidu.com/link?url=mehN7bFY14DGH6DwhpbJnAbzb_ Fi3wbqn2-wqvinyyqhkfylzsfu7gqvjqgqopv07tcfiqgiotvsqff-m9d-mk Open cmd, input: Sqlplus/nolog INPUT: Conn username/[email protected] Database name And of

In college when the major is the database management major, in the school learned a variety of data MSSQL, ORACLE, MySQL.At that time, most of the data learned only a few fur, only in accordance with the book SQL statements, input computer results,

Internet:Server-side: Be sure to start the listenerNo Configuration Boot listener: rm-f $ORACLE _home/network/admin/listener.oraView listening status: Lsnrctl statusStart monitoring: Lsnrctl startClient: Using service naming (network connection

Time Limit: 4000MS Memory Limit:262144KB 64bit IO Format:%i64d &%i64u DescriptionThere is once a king and queen, rulers of a unnamed city, who has three daughters of conspicuous beauty.The youngest and most beautiful are psyche, whose admirers,

--New UserCreate UserExample identified by 123456;--Delete UserDrop Userexample;--Lock UserAlter Userexample account lock;--Unlocking UsersAlter Userexample account unlock;--Modify User PasswordAlter UserExample identified by 654321;--grant

Single-table operation!(The code can be replaced by hand, written down for memory)1. Create a tableCREATE TABLE Hkb_table_modify(NAME VARCHAR2 (6),Age VARCHAR2 (3),SEX VARCHAR2 (2))2. Modify the tableAdd field: Alter TABLE hkb_table_modify add

This error occurs when the author performs a calculation of the number of rows that match the criteria, and reads the computed rows with OracleDataReader.The query statements are:Select Count (1) from Hp_ts Where ts_id>0The C # execution process

SELECT * from T_a A where A.begintime=to_date (' 2013-1-1 ', ' yyyy-mm-dd ');and theSELECT * from T_a A where To_char (a.begintime, ' yyyy-mm-dd ') = ' 2013-1-1 ';the query results are the same. the difference is that the processing steps of the

What is a view? ）1. A view is a database object, a virtual table that is exported from one or more data tables or views, and the data corresponding to the view is not really stored in the view, but is stored in the referenced data table, and the

Http://www.tuicool.com/articles/bI3IBvAttached problem: There is one SQL statement below:Select *from ( Select t.*, Row_number () over (frommytable t)WHERE RN between: And:end The ORDER BY statement in SQL greatly reduces the

User, table space, table:A user typically gives a table space, and multiple users can manage a table space togetherA table space will have more than one tableFor control of permissions:You can add a table between the people menu table and the file