/// <summary>
/// 根据类型生成Update 语句 必须输入条件
/// </summary>
/// <typeparam name="T">数据类型。</typeparam>
/// <param name="conditions">条件 "例如：ID=@ID"</param>
/// <param name="keyName">条件 主键列一般是不能更新的 所以要过滤掉。</param>
/// <returns></returns>
public static string GetUpdateCommandStringByType <T>(string conditions, string keyName) where T : class
{
if (string.IsNullOrEmpty(conditions) || string.IsNullOrWhiteSpace(conditions))
{ //防止误操作 更新所有数据~
throw new Exception("为保证数据库安全，更新语句必须提供更新范围条件！");
}
PropertyInfo[] properties = DapperPagerUtils.GetPropertyInfosByType(typeof(T)).ToArray();
var columns = properties.Where(o => !o.Name.Equals(keyName)).Select(p => p.Name).ToArray();
var parameters = columns.Select(name => "[" + name + "]" + "=@" + name).ToList();
string str = String.Format(updateString, typeof(T).Name, String.Join(",", parameters));
//if (!string.IsNullOrEmpty(keyName))
//{
// str = str.Replace("@" + keyName + ",", "").Replace(keyName + "=", "");
//}
if (string.IsNullOrEmpty(conditions))
{
return(str);
}
else
{
return(str + " AND " + conditions);
}
}
/// <summary>
/// 生成查询 WITH NO LOCK 语句 此模式在高并发下允许脏读 （相当于READ UNCOMMITTED）无法保证数据的一致性
/// 但是对性能较好。高并发情况下推荐使用此方法。
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public static string GetSelectWithNoLockCommandStringByType <T>(string conditions = "") where T : class
{
PropertyInfo[] properties = DapperPagerUtils.GetPropertyInfosByType(typeof(T)).ToArray();
var columns = properties.Select(p => "" + p.Name + "").ToArray();
string str = string.Format(selectStringWithNoLock, String.Join(",", columns), typeof(T).Name);
if (string.IsNullOrEmpty(conditions))
{
return(str);
}
else
{
return(str + " AND " + conditions);
}
}
/// <summary>
/// 生成过滤掉标识列的SQL插入语句命令
/// </summary>
/// <typeparam name="T">泛型类名</typeparam>
/// <param name="keyName">标识列名称</param>
/// <returns></returns>
public static string GetInsertCommandFilteredIdentityColumn <T>(string keyName) where T : class
{
PropertyInfo[] properties = DapperPagerUtils.GetPropertyInfosByType(typeof(T)).ToArray();
if (properties.Count() < 1)
{
throw new Exception("传入对象不具有属性，请检查传递对象！");
}
var columnsCommand = properties.Where(o => !o.Name.Equals(keyName)).Select(p => "[" + p.Name + "]").ToArray();
var columnsValue = properties.Where(o => !o.Name.Equals(keyName)).Select(p => p.Name).ToArray();
return(string.Format(insertString,
typeof(T).Name,
String.Join(",", columnsCommand), properties[0].Name,
String.Join(",@", columnsValue)));
}
