/// <summary>
/// 指定实体类型映射器、视图映射器和条件创建一个查询的命令。
/// </summary>
/// <param name="entityMapper">实体的类型映射器。</param>
/// <param name="viewMapper">视图的类型映射器。</param>
/// <param name="where">条件参数。</param>
/// <param name="top">指定 TOP 数量，小于 1 则忽略作用。</param>
/// <param name="tunnel">用于个性化表名和命令的暗道，可以为 null 值。</param>
/// <returns>一个查询命令。</returns>
public virtual ExecuteCommand CreateQueryCommand(TypeMapper entityMapper, TypeMapper viewMapper, WhereParameters where, int top = 0, ICommandTunnel tunnel = null)
{
if(where == null) throw new ArgumentNullException(nameof(where));
if(tunnel == null) tunnel = Empty;
var fields = this.CreateFields(entityMapper, viewMapper);
if(top > 0) fields = string.Concat("TOP ", top.ToString(), " ", fields);
var commandText = string.Concat("SELECT ", fields, " FROM ", this.EscapeName(tunnel.GetTableName(entityMapper), NamePoint.Table));
return tunnel.GetCommand(entityMapper, new ExecuteCommand(where.AppendTo(commandText), where.Parameters));
}
/// <summary>
/// 指定类型映射器和条件参数创建一个表总行数的命令。
/// </summary>
/// <param name="mapper">类型映射器。</param>
/// <param name="where">条件参数。</param>
/// <param name="tunnel">用于个性化表名和命令的暗道，可以为 null 值。</param>
/// <returns>一个查询命令。</returns>
public virtual ExecuteCommand CreateRowCountCommand(TypeMapper mapper, WhereParameters where, ICommandTunnel tunnel = null)
{
if(mapper == null) throw new ArgumentNullException(nameof(mapper));
if(where == null) throw new ArgumentNullException(nameof(where));
if(tunnel == null) tunnel = Empty;
var commandText = "SELECT COUNT(*) FROM " + this.EscapeName(tunnel.GetTableName(mapper), NamePoint.Table);
return tunnel.GetCommand(mapper, new ExecuteCommand(where.AppendTo(commandText), where.Parameters));
}
/// <summary>
/// 指定类型映射器和实体创建一个更新的命令。
/// </summary>
/// <param name="mapper">类型映射器。</param>
/// <param name="entity">实体的实例对象。</param>
/// <param name="where">条件参数。</param>
/// <param name="tunnel">用于个性化表名和命令的暗道，可以为 null 值。</param>
/// <returns>一个查询命令。</returns>
public virtual ExecuteCommand CreateUpdateCommand(TypeMapper mapper, object entity, WhereParameters where, ICommandTunnel tunnel = null)
{
if(mapper == null) throw new ArgumentNullException(nameof(mapper));
if(entity == null) throw new ArgumentNullException(nameof(entity));
if(where == null) throw new ArgumentNullException(nameof(where));
if(tunnel == null) tunnel = Empty;
var setBuilder = new StringBuilder("UPDATE ")
.Append(this.EscapeName(tunnel.GetTableName(mapper), NamePoint.Table))
.Append(" SET ");
var ps = where.Parameters ?? new ExecuteParameterCollection(mapper.Count);
int index = 0;
foreach(var property in FindProperties(mapper, ref entity))
{
if(property.IsIgnore || property.IsKey) continue;
if(index++ > 0) setBuilder.Append(',');
setBuilder.Append(this.EscapeName(property.Name, NamePoint.Field))
.Append('=');
var value = property.GetValue(entity);
this.AppendParameterValue(property, setBuilder, value, ps);
}
if(index==0) throw new NotSupportedException($"{entity.GetType().FullName} 的更新操作没有找到任何属性。");
return tunnel.GetCommand(mapper, new ExecuteCommand(where.AppendTo(setBuilder.ToString()), ps));
}