PetaPoco 增删改查

1 查询单行 

DBInstance.DB.SingleOrDefault<CompanyInfo11>(id);

/// <summary>
/// 根据id获取公司信息
/// </summary>
/// <param name="id"></param>
/// <returns></returns>

public static CompanyInfo11 GetCompanyById(int id)
{
return DBInstance.DB.SingleOrDefault<CompanyInfo11>(id);

}

2 查询结果集

DBInstance.DB.Query<CompanyInfo11>("where 1=1 order by Cid desc").ToList()

        /// <summary>
        /// 查询所有公司信息，按创建日期倒序
        /// </summary>
        /// <returns>数据表格</returns>
        public List<CompanyInfo11> Load()
        {
            List<CompanyInfo11> companyList = null;
            companyList= DBInstance.DB.Query<CompanyInfo11>("where 1=1 order by Cid desc").ToList();
            return companyList;
        }

3 根据条件查询结果集

  /// <summary>
        /// 查询所有公司信息，根据参数
        /// </summary>
        /// <returns>数据表格</returns>
        public List<CompanyInfo11> Load()
        {
            List<CompanyInfo11> companyList = null;
            companyList = DBInstance.DB.Query<CompanyInfo11>("where Cid>@0", 5).ToList();//第一个参数是@0,第二个参数是@1,等等
            return companyList;
        }

4.1 Update 更新单表中一行

 /// <summary>
        /// 更新公司信息
        /// </summary>
        /// <param name="comp"></param>
        /// <returns></returns>
        public int Update(CompanyInfo11 comp)
        {
            if (comp != null)
            {
                  try
                {
                   int i= DBInstance.DB.Update(comp);
                    return i;
                }
                catch
                { }
            }

            return 0;
        }

　　

4.2 Update 更新单表中一行的某列

 /// <summary>
        /// 更新公司信息
        /// </summary>
        /// <param name="comp"></param>
        /// <returns></returns>
        public int Update(CompanyInfo11 comp)
        {
            List<string> columns = new List<string>();
            columns.Add("CompanyName");     //需要更新的列
            if (comp != null)
            {
                  try
                {
                   int i= DBInstance.DB.Update(comp,columns);
                    return i;
                }
                catch
                { }
            }

            return 0;
        }

4.3 Update 根据SQL语句(灵活)

//更新Cid>1000的所有条目，让CompanyName 都为实体类中的CompanyName
 public int Update(CompanyInfo11 comp)
        {

            int i = DBInstance.DB.Update<CompanyInfo11>("set CompanyName=@0 where Cid>@1",comp.CompanyName,1000);
            return i;
        }

　　

5.1 删除一行

public int Delete(CompanyInfo11 comp)
{
int i = DBInstance.DB.Delete(comp);
return i;
}

　　

5.2 带条件删除

public int Delete2()
        {
            int i = DBInstance.DB.Delete<CompanyInfo11>("where Cid>@0",1000);
            return i;
        }