zhuhongmingzhm

nvl( ) 函数 示例 请参阅 从两个表达式返回一个非 null 值。 语法 NVL(eExpression1, eExpression2) 参数 eExpression1, eExpression2 如果 eExpression1 的计算结果为 null 值，则 NVL( ) 返回 eExpression2。如果 eExpression1 的计算结果不是 nu...

取数字n的符号,大于0返回1,小于0返回-1,等于0返回0 [code="java"] SQL> select sign(100),sign(-100),sign(0) from dual; SIGN(123) SIGN(-100) SIGN(0) --------- ---------- --------- 1 -1 0 ...

Decode函数的语法结构如下: [code="java"] decode (expression, search_1, result_1) decode (expression, search_1, result_1, search_2, result_2) decode (expression, search_1, result_1, search_2, result_2, ......

1.ASCII 返回与指定的字符对应的十进制数; [code="java"] SQL> select ascii('A') A,ascii('a') a,ascii('0') zero,ascii(' ') space from dual; A A ZERO SPACE --------- --------- --------- ---...

[color=darkblue][size=large] [b] Oracle 体系结构[/b][/size][/color] [color=red][b]Oracle Server[/b][/color] Is a database management system that provides an open, comprehensive, integrat...

[size=large][color=blue]Oralce Architectural Components[/color][/size] [size=medium][color=red][b]Meroy Structure[/b][/color][/size] Oracle’s memory structure consists of two memory areas know...

Oralce Architectural Components Process Structure Oracle takes advantage of various types of processes: 1)        User process: Started at the time a database user requests connection to the Oracle...

          Oralce Architectural Components Logical Structure 1)        Dictates how the physical space of a database is used 2)        Hierarchy consisting of tablespaces,segments,extends and blocks...