existence

mysql stored procedures commonly used commands

See the wording on the stored procedure: http://trinea.iteye.com/blog/977141 mysql Chinese reference documentation see: http://dl.iteye.com/topics/download/82db8bb1-7c55-3e74-9f56-de5f8e004ded 0, stored procedures need to pay attention to the best an

Some disorderly thing

The INITRANS, chain line, and the efficiency of the data buffer to read my database using Oracle 9i. I have the following questions: 1, INITRANS parameter indicates the database block operation of the affairs of the concurrency level. This parameter

[Transfer] mysql event ---- syntax of CREATE EVENT

mysql event ---- syntax of the CREATE EVENT (2007-04-08 16:35:47) Reproduced Category: mysql A, EVENT relevant variables and parameters 1, the default start of the EVENT is not supported, can use the following command to view the status: Select @ @ e

Myeclipse6.5 how to install and configure plug-find bugs

findbugs eclipse is an open source code inspection tool; it can be simple and efficient comprehensive way to help us discover the existence of the program code bug, bad smell, and the potential risks. For a variety of issues, it provides a simple and

[Transferred] an example of a database. Two. Three and BCNF normal form

Database design paradigm is needed to meet database design specifications to meet these specifications database is simple, clear structure, at the same time, does not occur insert (insert), delete (delete) and update (update) operation exception. On

Table or record is locked after unlock

In the operation database, sometimes due to improper operation caused by database table is locked, so we always know what to do, I do not know how to unlock the tables in pl / sql Developer tools menu "tools" inside the "sessions"

SQL statement execution steps

SQL statement execution steps of a SQL statement process to go through the following steps. 1 analysis statement parsing the syntax of the specification. 2 Check the statement in the semantic analysis of all database objects related to the existence,

Room sql server 2005 to Sql server authentication settings landing

Room with the computer when the installation is the default windows authentication login, and we usually need to use login password to use on the network or remotely by other machines, so the need to use sql server authentication to log in online to

oracle daily performance check

Reproduced Competition to determine the rollback of the SQL statement: (Ratio greater than 2, when there is rollback competition, need to add more rollback segments) select rn.name, rs.GETS, rs.WAITS, (rs.WAITS / rs.GETS) * 100 ratio from v $ rollsta

Thesaurus expansion - Baidu Baike crawl - you know the hot word?

Do need a good Chinese word lexicon, these are basic online collection is not updated, there is no way that only their own entries in the crawl Baike. But Baike in more than 3 million entries, which should all crawl down to extract high-quality entri

Bank side of the socket communication receipt issued by the length of the high and low order header.

First, describe the scene, to do with java server in the case, to obtain the correct header (ie, packet length), I was listening to a more experienced colleague's question, said the case of banks with C may be obtained The length (int or short or

A series of questions about the database lock

How to use SQL statements to the database tables to lock and unlock?. Category: 1220 people read the database 2010-03-20 09:29 Comments (0) Add report Database lock is a very important concept, it is mainly used for multi-user environment to ensure databa

Ubuntu etc / passwd etc / shadow etc / group notes

/ Etc / passwd, / etc / shadow and / etc / group of the three configuration files for system account management, are text files that can be used to open a text editor such as vim. / Etc / passwd user account information for the store, / etc / shadow

java classes within the scenarios

Unsung heroes of the arena - On the Java class within the four scenarios Java is a Java language class within a very important concept, "Java programming ideas," spent a lot of space to talk about the concept. But we rarely used it in pract

where 1 = 1 or 0 = 0

sql where 1 = 1 0 = 1 and the role of where 1 = 1; this condition is always True, in the case of variable number of query, 1 = 1 can be easily standardized statement. First, no where 1 = 1 in a multi-criteria query trouble For example, if you do the

Operating on Oracle Merge

Hesitation project involves analysis of large data import, data each time before going into a database to determine the existence of this data for update and insert , The efficiency is not an ordinary slow - that Oracle9.2 Merge statement after a ver

select 1 from table meaning

1. Select 1 from ..., sql statement 1 mean? Check out what is the result? select 1 from table; and select anycol (the purpose of collection of any row in the table) from table; and select * from table is from the role of no difference, and see if the

Oracle [COLUMN] to set the table field default values ​​take effect only for the future

[COLUMN] to set the table field default values ​​take effect only for the next question: setting the table field's default value if the data will have to adjust the data? Answering such questions is the most effective way to "practice."

BT server set up within the network (switch)

My speaker Chuanzhi podcast. Net employment training class when the teacher during the day to live video recorded lectures for students at night, with a rest day review, the lectures during the day to six hours, so every day to more than one video G, has

Web page link test papers

Transformers project tour - "Link Test" article Transformers project tour ends quietly, many from the project needs change and confirmation, mockup / demo reviews ... development, testing, and maintenance of the product line up, licking the

index skip scan some of the experiments.

index skip scan a basic introduction. Table employees (sex, employee_id, address), a composite index (sex, employee_id). Jump in the index case, we can logically see them as two indexes, one (male, employee_id), one ( female, employee_id). select * f

log4j log file relative path

Have not been able to resolve well the log4j path to log file is saved today just encountered. Be more perfect solution. Let me talk about the scene: A web project, use log4j to do logging system when developing a web container for the jetty, the pro

ORACLE paging method

1 data table structure Table Name Authoring Field authoringId NUMBER PRIMARY KEY, name VARCHAR (50) NOT NULL, startDate Date 2. Page: startDate reverse page order Method 1 SELECT * FROM (SELECT a. *, row_number () OVER (ORDER BY a.STARTDATE DESC) row

[Transfer] mysql command-line commands and SQL statements, MySQL modify delete add field type, field data, etc. ..

I. Common mysql command-line command 1 Start service net start mysql MYSQL Stop service net stop mysql MYSQL 2. Netstat-na | findstr 3306 view was listening port, findstr to find the back of the port for the existence of 3. MYSQL landing on the comma

Oracle inner join and where the difference

1. WHERE clause using the connect statement in the database language, known as the hidden connection. INNER JOIN ... ... ON clause, resulting connection is called explicit connection. (Other parameters are also dominant JOIN connected) WHERE and INNE

sql on the field or table CRUD, sql statement Daquan

1. Increase the field alter table docdsp add dspcode char (200) 2 Remove the field ALTER TABLE table_NAME DROP COLUMN column_NAME 3. Modify field types ALTER TABLE table_name ALTER COLUMN column_name new_data_type 4.sp_rename renamed EXEC sp_rename '[

Summary database sql statement exists

Summary of the database exists sql statement sql exists in learning First to compare the following syntax: - Deals = transaction tables, areas = geographical tables, such as Hong Kong; Our goal: to view a regional trading select * from areas where id

weblogic11g db2 data source driver configuration problem

Today weblogic10.33 configure db2 9.7 data source, using type4 connected, drive select weblogic db2 type4 drive, the configuration is successful, open application test and found that the existence of meta-data access issues, such as through select *

sqlserver2000 on some statements to modify table structure

Add to delete SQL statements used to modify the field 1. Increase the field alter table docdsp add dspcode char (200) 2 Remove the field ALTER TABLE table_NAME DROP COLUMN column_NAME 3. Modify field types ALTER TABLE table_name ALTER COLUMN column_name n

oracle exists and not exist

Look at the following example: oracle in two system tables. Emp, dept. example: 1: not exists (not in) not exists: This statement returns the select * from scott.dept d where e.deptno = d.deptno and d.deptno = 10 conditions are met, the result set, i

The principles of database indexing

This article is from csdn (http://blog.csdn.net/yanshouke/archive/2008/12/18/3547518.aspx) An iron law: There is no free lunch, use index is a price to pay. Index obvious advantages, however, but few people cared about the index used to pay costs. If the

mysql command-line commands and SQL statements, MySQL modify delete increase the field type, field data, etc.

I. Common mysql command-line command 1 Start service net start mysql MYSQL Stop service net stop mysql MYSQL 2. Netstat-na | findstr 3306 view was listening port, findstr to find the back of the port for the existence of 3. MYSQL landing on the comma

Oracle: plan + execution statistics

db block gets: current mode, regardless of whether the data in this block may exist before image, that regardless of the existence rollback data can be rolled back, only to see the most current data block, even if someone else is being updated, but a

Oracle: soft and hard parsing + binding resolution spy

Speaking of soft parsing (soft prase) and hard parsing (hard prase), it can not be said about Oracle's sql processing. When you issue a sql statement delivered Oracle, and get the result in the implementation, Oracle sql this will be a few steps of th

Oracle: sql footprint and switching operation

sql mass action: where 1 = 1; this condition is always True, in the case of variable number of query, 1 = 1 can be easily standardized statement. First, no where 1 = 1 in a multi-criteria query trouble For example, if you do the query page, and can h

Advanced database transaction mechanism used (finishing)

Database transaction machine in front of the two blog, I wrote a bit about database locks in some of the content, and transaction locks are actually closely linked, that a transaction in the database is very important, but also more complex and implementa

powerDesigner use (construction of the index since added Check design models) --- turn

Model checking in the Existence of reference problem in the tool-> check model Select which option tab, then select the table, the next thing you start to understand Not duplicate the name, but by default you must create an index for each table / assoc

Brief: in.not in.exists not exists and the difference between

in, not in, exists and not exists a difference: the difference between in and exists: exists: there are generally behind the sub-query, when the number of rows returned by the subquery, exists returns true. select * from class where exists (select'x"

Oracle database to build the table space and user name and authorization, imp import database

Usually a software corresponds to a separate storage space, so data stored between multiple software will not affect each other. In SQLServer, usually with the "create database database name" to create a database. However, in Oracle, a serv

Some key words oracle application order

[, Str]: represents optional. 1: decode Usage: decode (value, search_value, result, defaultValue) Three similar projects in JAVA expression value == search_value? Result: defaultValue; 2: translate Usage: translate (x, exist_string, to_string) Exampl

Oracle dba and sysdba difference

Prior to the dba and sysdba always lumped together today to see the difference in the discussion forum, special records are as follows: SYSDBA is not a privilege, when the user logged in with SYSDBA database, users will log into SYS. Log in as sysdba

Oracle10g start the process

1. Nomount state to start the database parameter file reading process, the application parameter to start the instance. View the location of the database parameter file: show parameter spfile SQL> show parameter pfile; NAME TYPE VALUE ------------

Data file is successfully created, deleted

Data file does not create success alter database datafile'......' offline drop Then manually delete the data file but that there may be hidden Before we detail, we must more clearly: Oracle does not provide, such as deleting tables, views the same

oracle "unable to contact the agent please verify whether this proxy url null" solutions

Problem: Unable to get in touch with the agent. Verify that the proxy url is null After installation is complete, use your browser to log on to Enterprise Manager (http:// machine name: 1158/em /), log in using SYS user name is always prompt (state: state

Oracle SCN explain (original)

Overview of the SCN number SCN is updated when the Oracle database, maintained by the DBMS automatically increments to a cumulative figure. Oracle database, a total of four kinds of SCN were System checkpoint SCN: system checkpoint SCN in the control

In-depth understanding of SQL join query

SQL join query that we often used, including multi-table join queries into SQL: inner join, outer join, cross-connect, the following details on your knowledge of SQL join query for your reference. In connection with a column based on a common table t

PowerDesigner Skills Summary

Colleagues conclude the PD Caution, record it. Create table script generated by the pdm when the field exceeds 15 characters on the error (oracle) The solution is to open the PDM, Database menu bar will appear, enter the Database - Edit Current DBMS-

PL / SQL Advanced Control statements

• Introduction In any computer language (C, JAVA, pascal) has a variety of control statements (conditional statements, looping structures, sequence control structure) in pl / sql in the existence of such control structures. 1>: Using a variety of

Materialized view fast refresh

Fast refresh materialized view multi-table joins together June 22nd, 2007 | Categories: Boring | Tags: Leave a comment | Trackback Only article thanks YangTingKun students:) A materialized view problems to find him. Cause is the connected clustered SQL ta

A remote access solution to mysql error

A remote access solution to mysql error Tags: MySQL , remote access Today in the configuration of a server, how Rom this server mysql. Telnet normal in this machine to access your mysql properly. Error SQL Error (2003): Can't connect to MySQL server o
Recent
Recent Entries
Tag Cloud
Random Entries