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SQLite3 返回值解释

 

//成功返回SQLITE_OK ,即0
#define SQLITE_OK           0   /* Successful result */
/* beginning-of-error-codes */
//SQLITE 错误代码宏
#define SQLITE_ERROR        1   /* SQL error or missing database */
#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
#define SQLITE_PERM         3   /* Access permission denied */
#define SQLITE_ABORT        4   /* Callback routine requested an abort */
#define SQLITE_BUSY         5   /* The database file is locked */
#define SQLITE_LOCKED       6   /* A table in the database is locked */
#define SQLITE_NOMEM        7   /* A malloc() failed */
#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
#define SQLITE_NOTFOUND    12   /* NOT USED. Table or record not found */
#define SQLITE_FULL        13   /* Insertion failed because database is full */
#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
#define SQLITE_PROTOCOL    15   /* NOT USED. Database lock protocol error */
#define SQLITE_EMPTY       16   /* Database is empty */
#define SQLITE_SCHEMA      17   /* The database schema changed */
#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
#define SQLITE_MISMATCH    20   /* Data type mismatch */
#define SQLITE_MISUSE      21   /* Library used incorrectly */
#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
#define SQLITE_AUTH        23   /* Authorization denied */
#define SQLITE_FORMAT      24   /* Auxiliary database format error */
#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
#define SQLITE_NOTADB      26   /* File opened that is not a database file */
#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
/* end-of-error-codes */

三步解决Oracle数据库死锁

第一步:查看是否有死锁存在,查出有数据则代表有死锁  

select p.spid,c.object_name,b.session_id,b.oracle_username,b.os_user_name  from v$process p,v$session a,v$locked_object b,all_objects   c  
where  p.addr=a.paddr  
and    a.process=b.process  
and    c.object_id=b.object_id

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SQL中char,varchar 和nchar,nvarchar的区别

基础知识把握的不牢固,所以又在网上搜这个问题,看到这篇文章讲述的比较清楚,索性转载下来:(原文:olsonlowey)

Varchar 对每个英文(ASCII)字符都占用2个字节,对一个汉字也只占用两个字节
char 对英文(ASCII)字符占用1个字节,对一个汉字占用2个字节
Varchar 的类型不以空格填满,比如varchar(100),但它的值只是"qian",则它的值就是"qian"
而char 不一样,比如char(100),它的值是"qian",而实际上它在数据库中是"qian "(qian后共有96个空格,
就是把它填满为 100个字节)。

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MYSQL--事务处理(通俗易懂)

直以来我都以为MYSQL不支持事务处理,所以在处理多个数据表的数据时,一直都很麻烦(我是不得不将其写入文本文件,在系统重新加载得时候才写入数据库 以防出错)~今天发现MYSQL数据库从4.1就开始支持事务功能,据说5.0将引入存储过程^_^

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MYSQL字符乱码问题解决办法

初涉PHP和mysql的新手都可能会遇到一个头疼的问题:乱码!解决和规避乱码问题其实很简单,只要字符集统一,一般不会出现问题。这篇文章从实例讲解了如何解决mysql数据库的乱码问题。

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