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MySQL UNSIGNED和ZEROFILL属性

本文链接:https:blog.csdn.netu014427391articledetails102538878 UNSIGNED 这个属性就是标记数字类型是无符号的,和CC++语言中的unsigned 含义是一样的,int signed的类型范围是-2147483648~2147483648,而int unsigned的范围是0~4294967295这个属性使用时候可以在建表语句、加字段语句或者查询sql 里也是可以的create table t (a int unsigned)ENGINE=INNODB;select cast(a as signed integer);ZEROFILL 这个属性的意思是 ,如果宽度小于设定的宽度,则自动填充0,当然只是显示而已 ZEROFILL用在字段后面就可以,可以在建表语句、加字段语句alter table t change column a a int(4) unsigned zerofill;例子:CREATE TABLE t (a INT UNSIGNED)ENGINE=INNODB;INSERT INTO t SELECT 1;SELECT a,HEX(a) FROM

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ZEROFILL和UNSIGNED的区别【mysql】

一、解释1.UNSIGNED = unsigned = 无符号有符号包含负数,无符号不包含负数。对于正整数范围而言,无符号能存储的数据是有符号的两倍。 比如TINYINT类型,1字节即8位二进制即2的8次方,有符号能保存的数字范围为-128~127.无符号可以保存的范围为0~255.由此可知:unsigned的作用就是不能插入负数,如果插入负数默认为零 .ZEROFILL = zerofill = 填充0根据你所设置的类型长度,自动填充0比如你将类型长度设置4,当存入数字1时,数据库里面的值是这样的:0001二、实例数据库字段 tinyint类型1.unsigned

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    C- unsigned :1之位域分析

    mode:8; bit:模式选择 unsigned en:1; bit :使能选择 unsigned reserved:1; bit :保留reserved (也可以写成unsigned reserved :1;) unsigned clk_select:4; bit:时钟选择 unsigned ch_select:3; bit:通道选择}reg11; 定义一个reg11变量,不声明结构体的好处在于确保变量唯一性 en:1; bit :使能选择 unsigned reserved:1; bit :保留reserved(也可以写成unsigned reserved:1;) unsigned clk_select: unsigned c:1;}reg1;        位域总长度只有7位 struct reg{ unsigned a:4; unsigned b:2; unsigned c:32;}reg2; int a:4; unsigned b:1; unsigned c:2; unsigned d:1; }bit; }reg11; 使用typedef ,告诉编译器,reg11是个声明类型 int main()

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    unsigned int的世界不简单

    在C和C++的世界中,还有一种类型,叫做无符号数据,修饰符位unsigned,比如今天要说的unsigned int。引入特殊的类型,一方面带来了好处,一方面也留下了隐患。 一、有符号数与无符号数谁大谁小上代码:#include #include int main(){ int a = -1; unsigned int b = 1; if(a > b) printf(a >

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    Java中对于unsigned byte类型的转换处理问题由来Java中unsigned byte 的转换测试程序小结

    查询之后,发现原来Java中是没有unsigned byte type的。也就是说Java中所有的byte类型都是signed类型。 只能表达(-128127).而此处的代码为了读取像素值,所需要的值是(0255),所以需要的是unsigned byte而不是signed byte。 Java中unsigned byte 的转换正如上述我们看到的代码所示: int luminance = row & 0xFF; 首先widening类型。将byte声明为short或者int类型。 11111111 1111111 0xFF: 00000000 1111111 255: 00000000 1111111 所以这样,-1就转换成255.测试程序我们写了一个简单的程序对其进行Java unsigned byte 类型转换属于一个细节问题,由于java中没有内置unsigned byte类型,所以当我们需要使用其时,需要对signed byte 类型进行转换。

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    c++ int,unsigned int混合表达式类型转换

    ,有疑问欢迎添加QQ 2125364717,一起交流、一起发现问题、一起进步啊,哈哈哈哈哈 测试代码:#include#includeusing namespace std;int main() { unsigned

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    c# 获取串口设备的输入(unsigned char *和 char*)

    char, UINT8, UCHAR , BYTE System.Byte unsigned short, UINT16, USHORT, WORD, ATOM, WCHAR , __wchar_t System.UInt16 unsigned, unsigned int, UINT32, ULONG32, DWORD32, ULONG, DWORD, UINT System.UInt32 unsigned 如果DLL中有一个函数的传人参数是一个指针的话,如:int __stdcall FunctionName(unsigned char *param2)这就当是DLL的一个函数说明,返回值是INT,传入参数是一个指针 ,类型是unsigned char。 的地址,并FIX,就是固定“fixed 语句禁止垃圾回收器重定位可移动的变量”    {        int ret_value = inputpassword(array);这里传入的是指针,因为unsigned

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    Hyper-V 安装VM时出现the unsigned image’s hash is not allowed

    不过,当我虚拟一个Windows 7 来耍的时候,它居然提示我the unsigned image’s hash is not allowed日了狗了,win10 这个Hyper-v还真个性居然不让使用 链接在此https:superuser.comquestions1026190hyper-v-vm-wont-boot-from-cd-error-unsigned-images-hash-is-not-allowed

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    ARM(十三).WatchDog3

    #define rBANKCON1 (*(volatile unsigned *)0x48000008) BANK1 control#define rBANKCON2 (*(volatile unsigned unsigned *)0x4800002c) Mode register set for SDRAM#define rMRSRB7 (*(volatile unsigned *)0x48000030) unsigned char *)0x50000023)=(unsigned char)(ch)#define RdURXH0() (*(volatile unsigned char *)0x50000027 volatile unsigned char *)0x50004027)#define WrUTXH2(ch) (*(volatile unsigned char *)0x50008023)=(unsigned volatile unsigned char *)0x50008020)=(unsigned char)(ch)#define RdURXH2() (*(volatile unsigned char *

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    ARM(十二).ADC with IRQ3

    #define rBANKCON1 (*(volatile unsigned *)0x48000008) BANK1 control#define rBANKCON2 (*(volatile unsigned unsigned *)0x4800002c) Mode register set for SDRAM#define rMRSRB7 (*(volatile unsigned *)0x48000030) unsigned char *)0x50000023)=(unsigned char)(ch)#define RdURXH0() (*(volatile unsigned char *)0x50000027 volatile unsigned char *)0x50004027)#define WrUTXH2(ch) (*(volatile unsigned char *)0x50008023)=(unsigned volatile unsigned char *)0x50008020)=(unsigned char)(ch)#define RdURXH2() (*(volatile unsigned char *

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    ARM(十五).IIC with IRQ 3

    #define rBANKCON1 (*(volatile unsigned *)0x48000008) BANK1 control#define rBANKCON2 (*(volatile unsigned unsigned *)0x4800002c) Mode register set for SDRAM#define rMRSRB7 (*(volatile unsigned *)0x48000030) unsigned char *)0x50000023)=(unsigned char)(ch)#define RdURXH0() (*(volatile unsigned char *)0x50000027 volatile unsigned char *)0x50004027)#define WrUTXH2(ch) (*(volatile unsigned char *)0x50008023)=(unsigned volatile unsigned char *)0x50008020)=(unsigned char)(ch)#define RdURXH2() (*(volatile unsigned char *

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    ARM(十四).WatchDog with IRQ3

    #define rBANKCON1 (*(volatile unsigned *)0x48000008) BANK1 control#define rBANKCON2 (*(volatile unsigned unsigned *)0x4800002c) Mode register set for SDRAM#define rMRSRB7 (*(volatile unsigned *)0x48000030) unsigned char *)0x50000023)=(unsigned char)(ch)#define RdURXH0() (*(volatile unsigned char *)0x50000027 volatile unsigned char *)0x50004027)#define WrUTXH2(ch) (*(volatile unsigned char *)0x50008023)=(unsigned volatile unsigned char *)0x50008020)=(unsigned char)(ch)#define RdURXH2() (*(volatile unsigned char *

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    ARM(十一).ADC(3)

    #define rBANKCON1 (*(volatile unsigned *)0x48000008) BANK1 control#define rBANKCON2 (*(volatile unsigned unsigned *)0x4800002c) Mode register set for SDRAM#define rMRSRB7 (*(volatile unsigned *)0x48000030) unsigned char *)0x50000023)=(unsigned char)(ch)#define RdURXH0() (*(volatile unsigned char *)0x50000027 volatile unsigned char *)0x50004027)#define WrUTXH2(ch) (*(volatile unsigned char *)0x50008023)=(unsigned volatile unsigned char *)0x50008020)=(unsigned char)(ch)#define RdURXH2() (*(volatile unsigned char *

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    ARM(八).RTC(3)

    #define rBANKCON1 (*(volatile unsigned *)0x48000008) BANK1 control#define rBANKCON2 (*(volatile unsigned unsigned *)0x4800002c) Mode register set for SDRAM#define rMRSRB7 (*(volatile unsigned *)0x48000030) unsigned char *)0x50000023)=(unsigned char)(ch)#define RdURXH0() (*(volatile unsigned char *)0x50000027 volatile unsigned char *)0x50004027)#define WrUTXH2(ch) (*(volatile unsigned char *)0x50008023)=(unsigned volatile unsigned char *)0x50008020)=(unsigned char)(ch)#define RdURXH2() (*(volatile unsigned char *

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    ARM(三).UART with FIFO(3)

    #define rBANKCON1 (*(volatile unsigned *)0x48000008) BANK1 control#define rBANKCON2 (*(volatile unsigned unsigned *)0x4800002c) Mode register set for SDRAM#define rMRSRB7 (*(volatile unsigned *)0x48000030) unsigned char *)0x50000023)=(unsigned char)(ch)#define RdURXH0() (*(volatile unsigned char *)0x50000027 volatile unsigned char *)0x50004027)#define WrUTXH2(ch) (*(volatile unsigned char *)0x50008023)=(unsigned volatile unsigned char *)0x50008020)=(unsigned char)(ch)#define RdURXH2() (*(volatile unsigned char *

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    cpuimage 开源之

    char *R, const unsigned char *G, const unsigned char *B, unsigned char *H, unsigned char *S, unsigned char *V);void hsv2rgb(const unsigned char *H, const unsigned char *S, const unsigned char *V, unsigned char *R, unsigned char *G, unsigned char *B);void rgb2ycbcr(unsigned char R, unsigned char G, unsigned char B, unsigned char * y, unsigned char * cb, unsigned char * cr);void ycbcr2rgb(unsigned char y, unsigned char Cb, unsigned char Cr, unsigned char * R, unsigned char * G, unsigned char * B); ---------------

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    sar - Linux 系统监控利器

    ; unsigned long long cpu_idle; unsigned long long cpu_iowait; unsigned long long cpu_steal; unsigned long long frmkb; unsigned long long bufkb; unsigned long long camkb; unsigned long long tlmkb; unsigned long long frskb; unsigned long long tlskb; unsigned long long caskb; unsigned long long comkb; unsigned ; unsigned long long slabkb; unsigned long long kstackkb; unsigned long long pgtblkb; unsigned long long int rx; unsigned int tx; unsigned int frame; unsigned int parity; unsigned int brk; unsigned int overrun

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    Mac 使用 OpenMPClang

    ::__split_buffer(unsigned long, unsigned long, std::__1::allocator&) in seq-3efcea.o std::__1::deque: :__add_back_capacity() in seq-3efcea.o std::__1::__split_buffer::__split_buffer(unsigned long, unsigned ::__split_buffer(unsigned long, unsigned long, std::__1::allocator&) in seq-3efcea.o std::__1::deque: ::__split_buffer(unsigned long, unsigned long, std::__1::allocator&) in seq-3efcea.o std::__1::deque: allocate(unsigned long) in seq-3efcea.o std::__1::__split_buffer::__split_buffer(unsigned long, unsigned

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    根据字符串生成对应Hash值

    int length){ unsigned int b = 378551; unsigned int a = 63689; unsigned int hash = 0; unsigned int i ){ const unsigned int BitsInUnsignedInt = (unsigned int)(sizeof(unsigned int) * 8); const unsigned int ThreeQuarters = (unsigned int)((BitsInUnsignedInt * 3) 4); const unsigned int OneEighth = (unsigned ){ unsigned int hash = 0; unsigned int x = 0; unsigned int i = 0; for (i = 0; i < length; ++str, ++i) int length){ unsigned int seed = 131; * 31 131 1313 13131 131313 etc.. * unsigned int hash = 0; unsigned

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    快速高斯模糊算法

    void GaussianBlur(unsigned char* img, unsigned int x, unsigned int y, unsigned int w, unsigned int h, unsigned int comp, unsigned int radius){ unsigned int i, j ; radius = min(max(1, radius), 248); unsigned int cr, cg, cb; unsigned int xl, yl, yi, ym, riw; unsigned int read, ri, p, n; unsigned int imgWidth = w; unsigned int imgHeight = h; unsigned int imageSize = imgWidth*imgHeight; unsigned char * rgb = (unsigned char *)malloc(sizeof(unsigned char) * imageSize * 3); unsigned char * r = rgb; unsigned char

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