mysqlÊý¾Ý±íÖÐnullÓë¿Õ°×ÖµµÄÇø±ð
±íÁÐ×Ö¶ÎÔÚÎÞÖµµÄÇé¿öÏ ĬÈÏֵΪnullºÃ,»¹Êǿհ×ÖµºÃÄØ? 1)¶ÔÊý¾Ý²åÈë/²éѯ/µÄÓ°ÏìÈçºÎ? 2)¶Ô¸ÃÁнøÐÐË÷Òý,»áÓв»Í¬µÄЧÓÃô? ´ó¼ÒÒ»°ã¶Ô±êÌâ×ֶεÄλÊýÉèΪ¶àÉÙ?256 ÕýÎÄ×ֶεÄ?text? ¼¸Ç§ÍòÌõµÄÊý¾Ý´æ´¢,Òª±È½ÏÏÂÐÔÄÜ/¿Õ¼ä.
ÒýÓà ĬÈÏֵΪnullºÃ,»¹Êǿհ×ÖµºÃÄØ? 1)¶ÔÊý¾Ý²åÈë/²éѯ/µÄÓ°ÏìÈçºÎ? 2)¶Ô¸ÃÁнøÐÐË÷Òý,»áÓв»Í¬µÄЧÓÃô? ÄãÊÇ·ñÏëÇø·Ö ÎÞÖµ ºÍ '' ÕâÁ½ÖÖÇé¿ö£¿ ¼´×ֶεÄÖµÊÇÒ»¸ö¿Õ×Ö·û´®£¡ ÄãÌîдµµ°¸±íµÄʱºò£¬ÔÚÄãµÄÓÐÎÞ·¸×ï¼Ç¼ÕâÒ»À¸ÖУ¬ÊÇÁô¿Õ°×£¿»¹ÊÇÌî¡°ÎÞ¡± £¿ Ê×ÏÈÊÇÒµÎñÂß¼ÉϵÄÐèÇó¡£ ²åÈëÉϵÄÓ°Ïì²¢²»´ó£¬Ë÷ÒýÉÏÒ²²¢ÎÞ¶à´óÓ°Ïì¡£ ´ó¼ÒÒ»°ã¶Ô±êÌâ×ֶεÄλÊýÉèΪ¶àÉÙ?256 ±¾Éí¾ÍÊÇ varchar, ¶à´ó¶¼Ã»¹ØÏµ¡£ ÆäʵÊ×ÏÈÄã×Ô¼ºÐèÒª»Ø´ðÒ»¸öÎÊÌâ¡£ ÄãµÄ±êÌâ×»áÊǶàÉÙ£¿ ÕýÎÄ×ֶεÄ?text? ͬÉÏ£¬ÄãµÄÕýÎÄÄÚÈÝ£¬×ÊǶàÉÙ£¿ Ò»°ãÊÇÓà TEXT, MEDIUMTEXT, LONGTEXT. ÕâЩÎÊÌ⣬±ðÈ˲»¿ÉÄÜÖªµÀ£¬¹Ø¼üÊÇÄã×Ô¼ºµÄÒµÎñÉÏÐèÇóÊÇʲô¡£
Ïà¹ØÎÊ´ð£º
ÎÒÊÇÓÃmysql×Ô´øµÄC API if(mysql_real_connect(&mysql,"125.0.0.108","root","root","home",3306,NULL,0)) { AfxMessageBox("Êý¾Ý¿âÁ¬½Óʧ°Ü") ......
ÏÈÉÏ´íÎó ÎÞ·¨Áª½ÓÊý¾Ý¿â java.sql.SQLException: Before start of result set at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910) at com.mysql.jdbc.ResultSet.checkRowPos(ResultSet.java: ......
String SQL="insert into ѧÉúÐÅÏ¢±í values(StudentNumber,StudentName,StudentAge)";ÆäÖÐStudentNumber,StudentName,StudentAge¶¼ÊDZäÁ¿¡£ÕâÑùд²»¶Ô¡¡µ½µ×¸Ãզд°¡ Íò·Ö¸Ðл£¡ String SQL=&q ......
±í CREATE TABLE `ch1` ( `id` int(10) unsigned zerofill NOT NULL AUTO_INCREMENT, `no` int(10) unsigned DEFAULT NULL, `dtime` datetime DEFAULT NULL, PRIMARY KEY (`id ......
mysqlµÄÖ´ÐÐinsertÊÇ·ñÓзµ»ØÖµ£¿ÏñoracleµÄ·µ»ØÖµÊÇsqlcode£¬ mysqlÓзµ»ØÖµÃ´£¿Âé·³ÄÄλ¸æËßһϡ£ °ï¶¥ MYSQL½¨ÒéÈ¥ÆäËûÊý¾Ý¿â¿ª·¢°æ¿é mysqlÓзµ»ØÖµÃ´£¿ --- ÎÒÖªµÀmssqlÓУ¬@@error ²»ÖªµÀÓÐûÓÐÀàË ......