Oracle

Lock: VcD4KPHA + MS7NrMqxtPK/qsG9uPa0sL/fingerprint + uPy4xNDVw/ujusutz8jM4b27y62 + zc/fingerprint "http://www.2cto.com/uploadfile/Collfiles/20140421/2014042108535533.jpg" alt = "\"> 2. Row-Level Lock SELECT... For update

1. View and create an indexSelect * from user_indexes where table_name = 'student'Create index I _student_num on student (num)Ii. Notes on using Indexes① Type MatchingIf the num column in student is of the varchar type, select * from student where

This note is used to learn constraints, which are everywhere in the table. For example, data in a table cannot be empty or the table id must be set as the primary key. Constraint type: Primary key: The primary key represents a unique identifier in

I. No optimized speed: Executed in 69.436 seconds Drop table t purge;Create table t (x int );/* Clear the sharing pool. do not perform this operation in the production environment */Alter system flush shared_pool; Create or replace procedure

Running Environment: ubuntu + oracle 11.2.0 ORA-12547: TNS: lost contact error occurs when the command starts oracle. Good afternoon, no matter in the afternoon. If the link is invalid, it will not work after Shutdown and restart. Then google found

Create a tablespace Create tablespace ICITY datafile 'd: \ Oracle \ oradata \ orcl \ ICITY. dbf' size 400 M autoextend on next 10 M maxsize unlimited extent management local; Create temporary tablespace Create temporary tablespace ICITY_TEMP

Principle of Bitmap IndexingAdvantages of Bitmap indexes1. Quick statisticsBecause Bitmap indexes only store 0 and 1 fingers, the space occupied by Bitmap indexes is very small, and operations such as count (*) are very fast.2. Efficient ad hoc

1. Basic Principles Oracle logs: To improve hard disk write efficiency, Oracle uses a data buffer in the memory to store data and writes it to the disk (DBWR) after a certain amount or a certain amount of time ). In this case, if a fault such as

Preparations before installation: 1. Download the oracle Installation Package Http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html It must be noted that the current official website only provides installation files

I have learned several types of databases, such as mssqlserver and sqlite. Some basic logical and physical structures are similar. However, when I was in contact with oracle, I was confused about some concepts, here are some differences in the

The principle of consistent read is that the query record is determined by the time point of the query. Even if the query record changes later, the data at that point should be obtained based on the pre-image record of rollback and persistence. How

1.1 symptom description when an SQL command containing double quotation marks is executed to update the data table information, the system displays the following error message:For example:SQL> update group_table set grouppswd = "adbaadadf" where

1.1 symptom description when the following SQL statement is imported, garbled characters are displayed in the database. Insert into CONFERENCE (values, values, ACCESSNUMBER, ACCOUNTID, ALLOCATEDID, ALLOWVIDEOCONTROL, SCREENTYPE, values, BOARDNUM,

1. Create users and user groups # Groupadd dba-g [Group ID] dba # Groupadd dba-g [Group ID] oinstall # Useradd-c [comment]-g [main user group]-G [user group]-d/ora11g-m-u [user id]-o Ii. Decompress authorization The oracle Installation File is

-- Test environment:OS: Redhat linux (64)Primary:IP: 192.168.94.198SID: dgdb1Hostname: dg1DB_UNIQUE_NAME: dgdb1Database: 10.2.0.1 (64) Standby:IP: 192.168.94.199SID: dgdb1Hostname: dg2DB_UNIQUE_NAME: dgdb1_sDatabase: 10.2.0.1 (64)-- Preparations

Whether you do interpolation or other operations, an error is prompted that the ora-00054 resource is busy. There are two examples I have encountered: one is that the process has been killed but not completely released. The solution is as follows:

Control File -Small binary files -Define the current status of the physical database -The loss control file must be fixed. -Maintain database integrity -Requirements: 1. The database is in the mount state when it is started 2. Database

-- Create a tableCreate table sale_report (Sale_date date not null,Sale_item VARCHAR (2) not null,Sale_money DECIMAL (10, 2) not null,Primary key (sale_date, sale_item)); -- Test DataDECLAREV_begin_day DATE;V_end_day DATE;BEGINV_begin_day: = TO_DATE

10. Use the rpm installation package If there is a ready-made package locally, you can directly use rpm for installation. Rpm package name, but sometimes it needs the support of other packages, if you need to ignore this prompt, force installation,

Inner join) An internal join is also called an equivalent join. The returned result set is all the matched data in the two tables, and the unmatched data is discarded. That is to say, in this query, DBMS only returns relevant rows from the source