The database table has a physical existence in the database. A view is a virtual table, that is one that does not actually exist. View is made up of a query on one or many tables in a database. In database theory, a view is the result set of a stored…

Q: How do I see what the character set that a MySQL database, table and column are in? Is there something like SHOW CHARACTER SETFOR mydatabase; and SHOW CHARACTER SETFOR mydatabase.mytable; and SHOW CHARACTER SETFOR mydatabase.mytable.mycolumn; A: H…

官网文档:https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL 一.create table 1.官方字段 # # CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name -- (Note: TEMPORARY available in Hive 0.14.0 and later) [(col_name data_type […

Scenario Suppose we have a database table A, and then we create a CDS redirect view B for it, then every time the READ OPEN SQL is done on table A, ABAP kernel will direct this request to view B, and serve the request with content from B. Prerequisit…

<Windows Azure Platform 系列文章目录>  Azure SQL Database (19) Stretch Database 概览      Azure SQL Database (20) 使用SQL Server 2016 Upgrade Advisor      Azure SQL Database (21) 将整张表都迁移到Azure Stretch Database里      Azure SQL Database (22) 迁移部分数据到Azure Stretc…

Skip Headers Oracle® Database Patch 19121551 - Database Patch Set Update 11.2.0.4.4 (Includes CPUOct2014)   Released: October 14, 2014 This document is accurate at the time of release. For any changes and additional information regarding PSU 11.2.0.4…

primary database db_name=zwc, db_unique_name=zwc standby database db_name=zwc, db_unique_name=standby on primary database [oracle@vmdb12c ~]$ sqlplus sys/oracle@zwc as sysdba SQL*Plus: Release 12.1.0.1.0 Production on Thu Sep 26 16:12:10 2013 Copyrig…

使用duplicate target database ... from active database复制数据库 source db:ora11auxiliary db:dupdb 1.修改监听文件,静态注册监听 SID_LIST_ORA11 = (SID_LIST = (SID_DESC = (GLOBAL_DBNAME = ora11) (ORACLE_HOME = /u11/app/oracle/product//dbhome_1) (SID_NAME =ora11) ) (SID_DE…

DELETE DATABASE and DELETE USER statements delete all data tables, views, and macros from a database or user. The database or user remains in the Teradata Database as a named object and retains the available space. None of that space is any longer in…

问题描述: arcgis server10.1  arcgis sde10出现下面问题 Cannot connect to  database because the database client software failed to load. Be sure the database client software is installed and configured correctly. 由于数据库客户端软件无法加载,无法连接到数据库.请确保数据库客户端软件已安装和配置正确. 找原因:…

开始: 当前的tablesapce信息 pgsql=# select * from pg_tablespace; spcname | spcowner | spclocation | spcacl | spcoptions ------------+----------+-----------------------+--------+------------ pg_default | | | pg_global | | | tbs01 | /home/pgsql/tbs/tbs01 | | (…

Just do it: /* SQL 创建库 CREATE DATABASE jsp_demo DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci; SQL 创建表 CREATE TABLE `news` ( `iId` SMALLINT(6) NOT NULL AUTO_INCREMENT, `iCategory` TINYINT(4) NOT NULL, `sTitle` VARCHAR(100) NOT NULL, `sDesc` VARC…

--20170505 --塗聚文 Geovin Du CREATE DATABASE DuMailSystem GO USE DuMailSystem GO --1查詢表的及备注说明 SELECT Sysobjects.name AS TABLE_NAME, syscolumns.Id, syscolumns.name AS COLUMN_NAME, systypes.name AS DATA_TYPE, syscolumns.length as CHARACTER_MAXIMUM_LENGTH…

1.创建Filespace 创建Filespace必须是数据库超级用户( You must be a database superuser to create a filespace.)首先创建一个filespace的配置文件: [hadoop@hadoop hawq]$ hawq filespace -o hawqfilespace_config  #生成配置文件,只要配置了环境变量命令可以在任何目录下运行Enter a name for this filespace> testfs    #…

使用HAWQ   在HAWQ的使用上跟Greenplum基本就一样一样的了.比如:   1. 创建表空间 #选创建filespace,生成配置文件 [gpadmin@master ~]$ hawq filespace -o hawqfilespace_config Enter a name for this filespace > hawqfs Enter replica num , default replica num is used (default=) > Please specify…

DROP DATABASE [ IF EXISTS ] <数据库名> DROP table[ IF EXISTS ] <数据库表名> 语法说明如下: <数据库名>:指定要删除的数据库名. IF EXISTS:用于防止当数据库不存在时发生错误. DROP DATABASE:删除数据库中的所有表格并同时删除数据库.使用此语句时要非常小心,以免错误删除.如果要使用 DROP DATABASE,需要获得数据库 DROP 权限. 记得加IF EXISTS…

一)在同一个数据库服务器上面进行数据表间的数据导入导出: 1. 如果表tb1和tb2的结构是完全一样的,则使用以下的命令就可以将表tb1中的数据导入到表tb2中: insert into db2.tb2 select * from  db1.tb1 2. 如果表tb1和tb2只有部分字段是相同的,要实现将tb1中的部分字段导入到tb2中相对应的相同字段中,则使用以下命令: insert into db2.tb2(字段1,字段2,字段3……) select  字段1‘,字段2’,字段3‘,……  …

*************************** --判断数据库是否存在 IF EXISTS (SELECT * FROM MASTER..sysdatabases WHERE NAME = '库名') PRINT 'exists ' else PRINT 'not exists' *************************** -- 判断要创建的表名是否存在 IF EXISTS (Select * From sysObjects Where Name ='表名' And Type…

Set @TableName to the name of your table. declare @TableName sysname = 'TableName' declare @Result varchar(max) = 'public class ' + @TableName + ' {' select @Result = @Result + ' public ' + ColumnType + NullableSign + ' ' + ColumnName + ' { get; set;…

我们在学习MSBI的时候,经常会使用官方提供的Adventureworks和AdventureworksDW示例数据库,但是官方提供的数据量有点小, 以DW为例,Factinternetsales只有不到七万行的数据,我们很难做某些测试,譬如说想对事实表做一个分区测试,测试CUBE性能等. 为此,我想以FactInternetSales表为入口,扩大它的数据量到数亿条. 经过分析,我觉得只要把理解主键是怎么生成的,以及orderdatekey,duedatekey,shipdatekey修改下,…

昨天在工作中遇到一个情况,就是Development环境中的某台服务器上的某个数据库进入了Suspect状态.以前看书倒是知道说这个状态,不过实际工作当中从来没有遇到过.那么一些背景情况是这样的. 环境:Development 数据库产品:SQL Server 2008 R2 数据库业务类型:DataWare House 数据库恢复模式:Simple 备份情况:每天就一个备份 在Google上查询了相关资料加上自己对于这种情况已有的储备知识,首先我第一部先到SQL Server Log里面查找最…

w分布式查询.数据聚合.跨碎片join是可且应避免的.自增主键管理.基于-会话/事务/语句-选择碎片.通过-主键/模块/碎片索引-碎片化数据 http://www.agildata.com/database-sharding/ Database Sharding Challenges Due to the distributed nature of individual databases, a number of key elements must be taken into account:…

w主写从读.集群节点间时时内存复制.单表横切纵切.分析报表系统通过服务器联表 http://www.agildata.com/database-sharding/ Database Partitioning Options It has long been known that database partitioning is the answer to improving the performance and scalability of relational databases. Many…

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正常应用和数据库交互的过程是这样的, 其实我们也可以把部分应用逻辑放到DB端去执行,来提升效率 User-defined Function Stored Procedures Triggers Change Notification User-defined Types Views UDF 用户定义的function,往往用于select中,不会修改数据本身 UDF可以用SQL实现,也可以用外部语言,右边是PG的例子 Stored Procedure 存储过程,可以理解成在数据库上执行一个脚本…

http://www.onjava.com/pub/a/onjava/2001/05/30/optimization.htmlComparing the performance of LinkedLists and ArrayLists (and Vectors) (Page last updated May 2001, Added 2001-06-18, Author Jack Shirazi, Publisher OnJava). Tips: ArrayList is faster than…

  Preface       We've used pt-table-checksum to checksum the different table data bwtween replication master and slaves yesterday.In this case,i'll use another of of Percona-Toolkit called "pt-table-sync" to sync these difference.These two instr…

pt-heartbeat是用来监测主从延迟的情况的,众所周知,传统的通过show slave status\G命令中的Seconds_Behind_Master值来判断主从延迟并不靠谱. pt-heartbeat的思路比较巧妙,它在master中插入一条带有当前时间(MySQL中的now()函数)的记录到心跳表中,然后,该记录会复制到slave中.slave根据当前的系统时间戳(Perl中的time函数)减去heartbeat表中的记录值来判断主从的延迟情况.具体,可参考下面--skew参数的说…

Zabbix3.0 Server以后就自带了MySQL插件来监控mysql数据库的模板,只需要配置好agent客户端,然后在web端给主机增加模板就行了. 以下是公司线上的zabbix3.0环境下添加mysql监控操作记录: Zabbix_agent客户端操作1)首先在客户端的mysql里添加权限,即本机使用zabbix账号连接本地的mysqlmysql> grant all on *.* to zabbix@'localhost' identified by "123456”;mysql…

BIND-DLZ实验:http://bind-dlz.sourceforge.net/ 实验环境:RHEL4,BIND-9.5.0-P2.tar.gz(9.4.0以上版本都已含DLZ补丁),Mysql-5.0.56.tar.gz 1.安装mysql(先安装gcc等相关软件包)    #tar zxvf mysql-5.0.56.tar.gz    #cd mysql-5.0.56   #./configure --prefix=/usr/local/mysql --localstatedir=/…