create procedure Pro_GenerateID
(
@tableName varchar(50), --要產生遞增號的表名
@columnName varchar(50), --要產生遞增號的列名
@signID varchar(20) --標記符,如是以G-1,G-2,G-3...形式遞增,如果給@signID傳遞'G-'則返回G-4
)
as
declare @signLength int, --@signID的長度
@strScript varchar(800), --產生遞增id的sql字符串
@strIntScript varchar(200) --當前表最大ID號的sql字符串
set @signLength = len(@signID)
select @strIntScript='cast(substring(' + @columnName +
',' + cast((@signLength + 1) as varchar(20)) + ',(select max(len(' + @columnName + ')) from ' + @tableName +')-' +cast(@signLength as varchar(20)) + ') as int)'
select @strScript='select top 1 (''' + @signID + ''' + cast((' + @strIntScript + '+1) as varchar(20))) as id from ' + @tableName + ' where left(' + @columnName + ',' + cast(@signLength as varchar(20)) + ')=''' + @signID + ''' order by ' + @strIntScript + ' desc'
select @strScript='if(exists(select * from ' + @tableName + ' where ' + @columnName + ' like ''' + @signID + '%''))
' + @strScript +'
else
select ''' + (@signID +'1') + ''' as id'
print @strScript
exec(@strScript)
如果在ccc表中沒有數據
執行此存儲過程:exec Pro_GenerateID 'ccc','c1','G-'
顯示結果爲:
id
------
G-1
(返回 1 行)
在c#中定義類可以寫:
Public Class GenerateIncreaseID{
public static string GetNewID(string tableName,string columnName,string signID){
SqlConnection con = new SqlConnection("...");
SqlCommand com = new SqlCommand("Pro_GenerateID",con);
com.CommandType = CommandType.StoredProcedure;
com.Parameters.Add(new SqlParameter("@tableName",tableName));
com.Parameters.Add(new SqlParameter("@columnName",columnName));
com.Parameters.Add(new SqlParameter("@signID",signID));
try{
con.Open();
return com.ExecuteScalar().ToString();
}
catch(Exception ex){
throw(ex);
}
finally{
if(con.State == ConnectionState.Open){
con.Close();
}
con = null;
com = null;
}
}
}
調用時只需:
string s = GenerateIncreaseID.GetNewID("ccc","c1","G-");
可以用此方法來生成有規則主鍵,表中標識符等.