asp.net·Àsql×¢Èë
using (con)
{
con.Open();
String sqltext = "select * from emp where empno=@empno";
SqlCommand cmd = new SqlCommand(sqltext, con);
cmd.Parameters.AddWithValue("@empno", this.TextBox.Text);
GridView1.DataSource = cmd.ExecuteReader();
GridView1.DataBind();
}
¼´Ê¹ÓòÎÊý»¯£¬¶ø²»ÊÇÖ±½ÓÆ´½ÓsqlÓï¾ä£¬¼òµ¥ÓÐЧ£¬ÄÜ»ù±¾Ó¦¶ÔÍøÕ¾µÄÒ»°ã°²È«ÒªÇó¡£µ«ÊÇÿ¸ösqlÓï¾äÓÖÒª²ÎÊý»¯£¬¶ÔÓÚ²ÎÊý±È½Ï¶àµÄÓï¾äдÆðÀ´±È½ÏÂé·³¡£
Ïà¹ØÎĵµ£º
ÓеÄʱºò£¬ÎÒÃÇÓÐÐèÒª½«Óɲ»Í¬À¸Î»»ñµÃµÄ×ÊÁÏ´®Á¬ÔÚÒ»Æð¡£Ã¿Ò»ÖÖ×ÊÁϿⶼÓÐÌṩ·½·¨À´´ïµ½Õâ¸öÄ¿µÄ£º
MySQL: CONCAT()
Oracle: CONCAT(), ||
SQL Server: +
CONCAT() µÄÓï·¨ÈçÏ£º
CONCAT(×Ö´®1, ×Ö´®2, ×Ö´®3, ...): ½«×Ö´®1¡¢×Ö´®2¡¢×Ö´®3£¬µÈ×Ö´®Á¬ÔÚÒ»Æð¡£Çë×¢Ò⣬OracleµÄCONCAT()Ö»ÔÊÐíÁ½¸ö²ÎÊý£»»»ÑÔÖ®£¬Ò ......
±í¸ñÊÇÊý¾Ý¿âÖд¢´æ×ÊÁϵĻù±¾¼Ü¹¹¡£ÔÚ¾ø´ó²¿·ÝµÄÇé¿öÏ£¬Êý¾Ý¿â³§É̲»¿ÉÄÜÖªµÀÄúÐèÒªÈçºÎ´¢´æÄúµÄ×ÊÁÏ£¬ËùÒÔͨ³£Äú»áÐèÒª×Ô¼ºÔÚÊý¾Ý¿âÖн¨Á¢±í¸ñ¡£ËäÈ»Ðí¶àÊý¾Ý¿â¹¤¾ß¿ÉÒÔÈÃÄúÔÚ²»ÐèÓõ½ SQL µÄÇé¿öϽ¨Á¢±í¸ñ£¬²»¹ýÓÉÓÚ±í¸ñÊÇÒ»¸ö×î»ù±¾µÄ¼Ü¹¹£¬ÎÒÃǾö¶¨°üÀ¨ CREATE TABLE µÄÓï·¨ÔÚÕâ¸öÍøÕ¾ÖС£
ÔÚÎÒÃÇÌøÈë CREATE TABL ......
Ö÷¼ü (Primary Key) ÖеÄÿһ±Ê×ÊÁ϶¼ÊDZí¸ñÖеÄΨһֵ¡£»»ÑÔÖ®£¬ËüÊÇÓÃÀ´¶ÀÒ»ÎÞ¶þµØÈ·ÈÏÒ»¸ö±í¸ñÖеÄÿһÐÐ×ÊÁÏ¡£Ö÷¼ü¿ÉÒÔÊÇÔ±¾×ÊÁÏÄÚµÄÒ»¸öÀ¸Î»£¬»òÊÇÒ»¸öÈËÔìÀ¸Î» (ÓëÔ±¾×ÊÁÏûÓйØÏµµÄÀ¸Î»)¡£Ö÷¼ü¿ÉÒÔ°üº¬Ò»»ò¶à¸öÀ¸Î»¡£µ±Ö÷¼ü°üº¬¶à¸öÀ¸Î»Ê±£¬³ÆÎª×éºÏ¼ü (Composite Key)¡£
Ö÷¼ü¿ÉÒÔÔÚ½¨ÖÃбí¸ñʱÉ趨 (ÔËÓà CREA ......
µ½Ä¿Ç°ÎªÖ¹£¬ÎÒÃÇѧµ½Á˽«ÈçºÎ°Ñ×ÊÁÏÓɱí¸ñÖÐÈ¡³ö¡£µ«ÊÇÕâЩ×ÊÁÏÊÇÈç¹û½øÈëÕâЩ±í¸ñµÄÄØ£¿ Õâ¾ÍÊÇÕâÒ»Ò³ (INSERT INTO) ºÍÏÂÒ»Ò³ (UPDATE) ÒªÌÖÂ۵ġ£
»ù±¾ÉÏ£¬ÎÒÃÇÓÐÁ½ÖÖ×÷·¨¿ÉÒÔ½«×ÊÁÏÊäÈë±í¸ñÖÐÄÚ¡£Ò»ÖÖÊÇÒ»´ÎÊäÈëÒ»±Ê£¬ÁíÒ»ÖÖÊÇÒ»´ÎÊäÈëºÃ¼¸±Ê¡£ ÎÒÃÇÏÈÀ´¿´Ò»´ÎÊäÈëÒ»±ÊµÄ·½Ê½¡£
ÒÀÕÕ¹ßÀý£¬ÎÒÃÇÏȽéÉÜÓï·¨¡£Ò»´ÎÊäÈ ......