private static DbCommand GetUpdateCommand <TEntity>(this Table <TEntity> table, Expression <Func <TEntity, bool> > filter, Expression <Func <TEntity, TEntity> > evaluator) where TEntity : class
{
DbCommand command = (table.Context as SqlDataContext).SqlCommand;
command.CommandType = CommandType.Text;
command.Parameters.Clear();
//查询条件表达式转换成SQL的条件语句
ConditionBuilder builder = new ConditionBuilder();
builder.Build(filter.Body, command);
string commandWhere = command.CommandText;
var set = new StringBuilder();
var entityType = typeof(TEntity);
var metaTable = table.Context.Mapping.GetTable(entityType);
var tableName = "[" + metaTable.TableName + "]";
evaluator.Visit <MemberInitExpression>(delegate(MemberInitExpression expression)
{
set.Append(GetDbSetStatement <TEntity>(expression, table, command));
return(expression);
});
command.CommandText = "UPDATE " + tableName + " " + set + " WHERE " + commandWhere;
return(command);
}
/// <summary>
/// 删除数据
/// </summary>
public static int Delete <TEntity>(this Table <TEntity> table, Expression <Func <TEntity, bool> > filter) where TEntity : class
{
DbCommand cmd = (table.Context as SqlDataContext).SqlCommand;
cmd.CommandType = CommandType.Text;
cmd.Parameters.Clear();
//查询条件表达式转换成SQL的条件语句
ConditionBuilder builder = new ConditionBuilder();
builder.Build(filter.Body, cmd);
string commandWhere = cmd.CommandText;
//获取表名
string tableName = "[" + table.Context.Mapping.GetTable(typeof(TEntity)).TableName + "]";
//SQL命令
string commandText = string.Format("DELETE FROM {0} WHERE {1}", tableName, commandWhere);
cmd.CommandText = commandText;
if (table.Context.Connection.State != ConnectionState.Open)
{
table.Context.Connection.Open();
}
if (table.Context.Transaction != null)
{
cmd.Transaction = table.Context.Transaction;
}
return(cmd.ExecuteNonQuery());
}