Oracle 的规定，如果不varchar2 不指定长度，如何分配空间？ VARCHAR2(size [BYTE | CHAR]) Variable-length character string having maximum length size bytes or characters. Maximum size is 4000 bytes or characters, and minimum is 1 byte or 1 character. You must specify size for VARCHAR2. BYTE indicates that the column will have byte length semantics. CHAR indicates that the column will have character semantics. NUMBER [ (p [, s]) ] Number having precision p and scale s. The precision p can range from 1 to 38. The scale s can range from -84 to 127. Both precision and scale are in decimal digits. A NUMBER value requires from 1 to 22 bytes. ------------------------------------------------------------------------------ Blog： http://blog.csdn.net/tianlesoftware 网上资源： http://tianlesoftware.download.csdn.net 相关视频：http://blog.csdn.net/tianlesoftware/archive/2009/11/27/4886500.aspx DBA1 群：62697716(满); DBA2 群：62697977
Oracle 的规定，如果不varchar2 不指定长度，如何分配空间？ VARCHAR2(size [BYTE | CHAR])
Variable-length character string having maximum length size bytes or characters. Maximum size is 4000 bytes or characters, and minimum is 1 byte or 1 character. You must specify size for VARCHAR2.
BYTE indicates that the column will have byte length semantics. CHAR indicates that the column will have character semantics.
NUMBER [ (p [, s]) ]
Number having precision p and scale s. The precision p can range from 1 to 38. The scale s can range from -84 to 127. Both precision and scale are in decimal digits. A NUMBER value requires from 1 to 22 bytes.
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Blog： http://blog.csdn.net/tianlesoftware
网上资源： http://tianlesoftware.download.csdn.net
相关视频：http://blog.csdn.net/tianlesoftware/archive/2009/11/27/4886500.aspx
DBA1 群：62697716(满); DBA2 群：62697977
varchar2类型是要在内存块里面占据资源的，必须标示长度，才能分配内存空间。