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https://www.cnblogs.com/yoyaprogrammer/p/delta_variance.html 阅读全文
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CASE_NOT_FOUNDCASE selectorWHEN selector_value_1 THEN statements_1WHEN selector_value_2 THEN statements_2...WHEN selector_value_n THEN statements_n[ ELSE else_statements ]END CASE;]The simple CASE statement runs the first statements for which selector_valueequals selector. Remaining conditions are . 阅读全文
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Oracle权限设置一、权限分类：系统权限：系统规定用户使用数据库的权限。（系统权限是对用户而言)。实体权限：某种权限用户对其它用户的表或视图的存取权限。（是针对表或视图而言的）。二、系统权限管理：1、系统权限分类：DBA:拥有全部特权，是系统最高权限，只有DBA才可以创建数据库结构。RESOURCE:拥有Resource权限的用户只可以创建实体，不可以创建数据库结构。CONNECT:拥有Connect权限的用户只可以登录Oracle，不可以创建实体，不可以创建数据库结构。对于普通用户：授予connect, resource权限。对于DBA管理用户：授予connect，resource, db 阅读全文
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原创作品，允许转载，转载时请务必以超链接形式标明文章原始出处、作者信息和本声明。否则将追究法律责任。http://soulful.blog.51cto.com/468033/449934Environment variable ORACLE_UNQNAME not defined. Please set ORACLE_UNQNAME to database unique name.其实就是em的问题重新配置emca即可。以后注意之前设置好ORACLE_UNQNAME 。总结收藏：1，修改DBSNMP密码：重新配置DBCONSOLE，需要输入DBSNMP密码，但任何密码都会显示错误，需要预先修改 阅读全文
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File OperationsFormatted OutputFormatted InputCharacter Input and Output FunctionsDirect Input and Output FunctionsFile Positioning FunctionsError Functions 阅读全文
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The header <limits.h> defines constants for the sizes of integral types.The values below are acceptable minimum magnitudes; larger values may beused.CHAR_BIT 8 bits in a charCHAR_MAX UCHAR_MAX orSCHAR_MAXmaximum value of charCHAR_MIN 0 or SCHAR_MIN maximum value of charINT_MAX 32767 maximum va 阅读全文
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The header <time.h> declares types and functions for manipulating date and time. Somefunctions process local time, which may differ from calendar time, for example because of timezone. clock_t and time_t are arithmetic types representing times, and struct tm holds thecomponents of a calendar t 阅读全文
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9 Signals: <signal.h>The header <signal.h> provides facilities for handling exceptional conditions that arise duringexecution, such as an interrupt signal from an external source or an error in execution.void (*signal(int sig, void (*handler)(int)))(int)signal determines how subsequent s 阅读全文
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The declarations in <setjmp.h> provide a way to avoid the normal function call and returnsequence, typically to permit an immediate return from a deeply nested function call.int setjmp(jmp_buf env)The macro setjmp saves state information in env for use by longjmp. The return iszero from a dire 阅读全文
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7 Variable Argument Lists: <stdarg.h>The header <stdarg.h> provides facilities for stepping through a list of function arguments ofunknown number and type.Suppose lastarg is the last named parameter of a function f with a variable number ofarguments. Then declare within f a variable of t 阅读全文
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The assert macro is used to add diagnostics to programs:void assert(int expression)If expression is zero whenassert(expression)is executed, the assert macro will print on stderr a message, such asAssertion failed: expression, file filename, line nnnIt then calls abort to terminate execution. The sou 阅读全文
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5 Utility Functions: <stdlib.h>The header <stdlib.h> declares functions for number conversion, storage allocation, andsimilar tasks. double atof(const char *s)atof converts s to double; it is equivalent to strtod(s, (char**)NULL).int atoi(const char *s)converts s to int; it is equivalent 阅读全文
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4 Mathematical Functions: <math.h>The header <math.h> declares mathematical functions and macros.The macros EDOM and ERANGE (found in <errno.h>) are non-zero integral constants that areused to signal domain and range errors for the functions; HUGE_VAL is a positive double value.A d 阅读全文
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3 String Functions: <string.h>There are two groups of string functions defined in the header <string.h>. The first havenames beginning with str; the second have names beginning with mem. Except for memmove,the behavior is undefined if copying takes place between overlapping objects. Comp 阅读全文
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2 Character Class Tests: <ctype.h>The header <ctype.h> declares functions for testing characters. For each function, theargument list is an int, whose value must be EOF or representable as an unsigned char, andthe return value is an int. The functions return non-zero (true) if the argume 阅读全文
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1.7 Error FunctionsMany of the functions in the library set status indicators when error or end of file occur. Theseindicators may be set and tested explicitly. In addition, the integer expression errno (declaredin <errno.h>) may contain an error number that gives further information about the 阅读全文
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1.6 File Positioning Functionsint fseek(FILE *stream, long offset, int origin)fseek sets the file position for stream; a subsequent read or write will access databeginning at the new position. For a binary file, the position is set to offset charactersfrom origin, which may be SEEK_SET (beginning), 阅读全文
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1.5 Direct Input and Output Functionssize_t fread(void *ptr, size_t size, size_t nobj, FILE *stream)fread reads from stream into the array ptr at most nobj objects of size size. freadreturns the number of objects read; this may be less than the number requested. feofand ferror must be used to determ 阅读全文
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1.4 Character Input and Output Functionsint fgetc(FILE *stream)fgetc returns the next character of stream as an unsigned char (converted to anint), or EOF if end of file or error occurs.char *fgets(char *s, int n, FILE *stream)fgets reads at most the next n-1 characters into the array s, stopping if 阅读全文
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Formatted InputThe scanf function deals with formatted input conversion.int fscanf(FILE *stream, const char *format, ...)fscanf reads from stream under control of format, and assigns converted values throughsubsequent arguments, each of which must be a pointer. It returns when format is exhausted.fs 阅读全文