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1. EPM: Enterprises Project Management 2. Manhattan Project applied project management and systems engineering ideas and solutions.3. In 1917, Henrry L. Ganntt proposed the famous Gantt chart.4.  CPM: Critical Path Method    In 1957,Du Pont applied CP...

       很久没回itpub博客了，我“胡汉三”回来了。      不知从何时开始（上个月？这个月？），老毛病又犯了. 调节，调节。

（转载，原文地址：http://www.itpub.net/thread-1266395-1-1.html）在GROUP BY子句中多次使用一个列在GROUP BY子句中可以多次使用某个列，这样可以实现对数据的重新组织，或是按照不同的数据分组进行统计。例如，下面这个查询中包含一个GROUP BY子句，其中使用了两次division_id列，第一次是对division_id进行分组，第二次是在ROLLUP中使用。SQL> select division_id,job_id,sum(salary) 2 from employees2 3 group by division_id,rollup(division_id,job_id);DIV JOB SUM(SALARY)--- --- -----------BUS MGR 530000BUS PRE

(转载，原文地址：http://blog.csdn.net/huang_xw/article/details/6402396)Oracle的group by除了基本用法以外，还有3种扩展用法，分别是rollup、cube、grouping sets。1 rollup假设有一个表test，有A、B、C、D、E5列。如果使用group by rollup(A,B,C)，首先会对(A、B、C)进行GROUP BY，然后对(A、B)进行GROUP BY，然后是(A)进行GROUP BY，最后对全表进行GROUP BY操作。roll up的意思是“卷起”，这也可以帮助我们理解group by rollup就是对选择的列从右到左以一次少一列的方式进行grouping直到所有列都去掉后的grouping(也就是全表groupi

TheApplicationOfTheInitialValueInForms6i--Eric, Jun 14, 2009This chapter introduces the application of the initial vaule in Oracle Forms 6i.SYSTEM.RECORD_STATUSSYSTEM.RECORD_STATUS represents the status of the record where the cursor is located. The value can be one of four character strings: Value DefinitionCHANGED Indicates that a queried record's validation status is Changed. INSERT Indicates that the record's validation status is Changed and

TimingStatisticsInDifferentSqlplusVersion --Eric, Jun 13, 2009This chapter introduces the different display mode of timing statistics between SQL*PLUS 8.0 and SQL*PLUS 10.2.In the fixed SQL*PLUS version , the display mode can’t be modified.SQL*PLUS8.0In SQL*PLUS 8.0, if you execute the command “set timing on”, when we execute a SQL command , the display of timing statistics’s mode is millisecond, not our normal time. SQL*Plus: Release 8.0.6.0.0 - Production on Sat Ju

DifferenceBetweenSQLAndPLSQLScott Urman: 过程化的语言都是线性语言，例如PL/SQL，它们以Begin开始，以End结束。虽然这只是非常简化的定义，但是它指出了过程化语言与面向对象语言之间的最根本的区别，每一条语句都必须等到它之前的语句执行完毕之后才能执行。在PL/SQL的特性中，笔者所喜欢的不是它与数据库的紧密结合(虽然它与数据库结合得非常完美)，不是它拥有的高级语言的概念很功能，也不是它提供的某种功能，笔者所钟爱的是它结构化的程序设计方法。每一个BEGIN都会有一个END;每一个IF，都会有一个END IF. PL/SQL是一种结构化的、

OracleNULL --Eric, Jun 14, 2009 PL/SQL treats a string of zero-length as a NULL.A zero-length string is two single quotes without any characters in between.The following two assignments are equivalent: my_sting :=NULL; my_sting :=’’;[@more@]

OracleCharacterOracleCharacterDatatypeDatatype DefinitionVARCHAR2(size) Variable-length character string having a maximum of size bytes (up to 4000).CHAR(size) Fixed-length character data, size characters long. Maximum size is 2000.Default is 1 byte. Padded on the right with blanks to full length of size.OracleCharacterFunctionFunction DefinitionLENGTH(string) This tells the LENGTH of a string.CHR(integer) CHR gives the character with an ASCI

从功能上划分，SQL语言可以分为DDL,DML和DCL三大类。 1. DDL（Data Definition Language） 数据定义语言，用于定义和管理 SQL 数据库中的所有对象的语言 ； CREATE---创建表 ALTER---修改表 DROP---删除表 2. DML（Data Manipulation Language） 数据操纵语言，SQL中处理数据等操作统称为数据操纵语言 ； INSERT---数据的插入 DELETE---数据的删除 UPDATE---数据的修改 SELECT---数据的查询 DCL（Data Control Language） 数据控制语言，用来授予或回收访问数据库的某种特权，并控制数据库操纵

We can insert NULL into a column of a table.There are two examples,let's see the difference.1、INSERT INTO table_name VALUES( id,NULL);This method inserts NULL to a column of the table. 2、INSERT INTO table_name VALUES( id,'');This method doesn't insert NULL into the column ofthe table,because '' is a valid value,though it is a empty string.[@more@]

TRUNCATE is faster than DELETE ,because it doesn't make a note of the change of the data.[@more@]

INSTR(表的某个字段,'外部传入的值') 1、INSTR(c1,c2[,n1[,n2]]) 返回c2在c1中位置l c2:要寻找的字符串l n2:第几个匹配项。大于0例如： INSTR(,,-) DUAL;[@more@]

If the report filename is test.rdf ,but the report name is test_1,then the complied report filename is test_1.rep.[@more@]

1、UNION 中的每个查询必须包含相同的列、表达式或聚集函数(不过各个列不需要以相同的次序列出)2、列数据类型必须兼容：类型不必完全相同，但必须是DBMS可以隐含转换的类型(例如不同的数值类型或不同的日期类型)The following script gives some examples.[@more@]SQL> COLUMN cust_name FORMAT A20SQL> COLUMN cust_contact FORMAT A20SQL> COLUMN cust_email FORMAT A25SQL> SELECT cust_name,cust_contact,cust_email FROM customers;CUST_NAME CUST_CONTACT CUST_EMAIL -------------------- -------------------- ------

If you use AVG() with distinct ,it will raise the average value.[@more@]

You can see the usage of NULL with function by the following scripts.FUNCTION:AVG()、COUNT()、SUM() AVG(): It doesn't consider the column which is null.If the record has 5 rows,the specified column has 3 real values and 2 null values,the AVG equals: the summmary of the 3 real value divied 3.(not 5)COUNT():It doesn't consider the column which is null.If the record has 5 rows,the specified column has 3 real values and 2 null values,the count equals:3(not 5)SUM():It doesn't consider the column whic

很久没有安装过FORM了，因为自己电脑基本半个月做一次GHOST，所以，常用的软件，很少会安装多次，这几日，自己的同事，被FORM的安装折腾的够呛，后来将瑞星给卸掉，再安装，就很顺利，在此，想给安装FORM6i的朋友提个醒，如果安装过程中，出现问题，请检查一下，是不是杀毒软件在作怪。[@more@]

Form中屏蔽默认功能键！[@more@]方法如下:1> 添加Form级触发器“KEY-OTHERS” 2〉在Form级触发器“KEY-OTHERS”中写如下代码： null;3〉 这样FORM程序运行后，大部分的功能键都被屏蔽（包括一些必需键，如：上箭头、下箭头、退出...），要想让这些键再恢复功能，就为这些键各自编程： 按键触发器代码说明上箭头KEY-DOWNDOWN;上滚记录下箭头KEY-UPUP;下滚记录Page UpKEY-SCRUPSCROLL_UP;上翻屏Page DownKEY-SCRDOWNSCROLL_DOWN;下翻屏F1KEY-HELPHELP;显示帮助F3KEY-DUP-ITEMDUPLICATE_ITEM;复制项F4KEY-DUPRECDUPLICATE_RECORD;复制记录

One DOS batch command can copy a source dir to object dir which will be auto named by the current date.[@more@]/**************************************************Creator: Eric Zhao(English name)Zhaofei(Chinese name)Date: 2007-11-08Object: Copy a source dir to object dir which willbe auto named by the current date.source dir: D:1object dir: D:%date:~0,4%%date:~5,2%%date:~8,2%--The following command is the batch command.@echo offxcopy D:1 D:%date:~0,4%%date:~5,2%%date:~8,2%echo exit;**************