using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WeighBusiness.Utils.SqlUtils
{
	public class DeleteUtil
	{
		/// <summary>
		/// 获取删除Sql语句。
		/// </summary>
		/// <param name="table">表</param>
		/// <param name="keyColumn">条件的列名</param>
		/// <param name="keyColumnValues">条件的值</param>
		public static string GetDeleteString(string table, string keyColumn, params string[] keyColumnValues)
		{
			string deleteSql = string.Empty;
			if (keyColumnValues == null || keyColumnValues.Length == 0)
				return deleteSql;
			string format = string.Format(@"delete from {0} where {1}=", table, keyColumn);
			deleteSql = format + "'" + string.Join("' or " + keyColumn + " = '", keyColumnValues) + "'";
			return deleteSql;
		}

		public static string GetDeleteTableSql(string table)
		{
			return "drop table " + table;
		}

		public static bool DeleteTableIfExist(string table)
		{
			string errorMessage;
			return DeleteTableIfExist(table, out errorMessage);
		}

		public static bool DeleteTableIfExist(string table, out string errorMessage)
		{
			errorMessage = string.Empty;
			if (!SqlUtilBase.IsDatabaseExist())
				return true;
			if (SqlUtilBase.IsTableExist(table)) {
				var deleteSql = GetDeleteTableSql(table);

				return SqlHelperEx.DoExecuteNonQuery(deleteSql, out errorMessage);
			}
			return true;
		}

	}
}