/// <summary>
/// 生成一个带别名的子查询
/// </summary>
/// <param name="aliasName"></param>
/// <returns></returns>
public TableRelation <TSub> SubQuery <TSub>(string aliasName)
where TSub : Entity
{
TableRelation <TSub> tr = new TableRelation <TSub>(null);
tr.section.SetQuerySection(section.SubQuery <TSub>(aliasName));
return(tr);
}
/// <summary>
/// 返回一个From节
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public FromSection <T> From <T>(TableRelation <T> relation)
where T : Entity
{
FromSection <T> section = From <T>();
section.SetQuerySection(relation.Section.Query);
//给查询设置驱动与事务
section.Query.SetDbProvider(dbProvider, this);
return(section);
}
/// <summary>
/// 返回一个Query节
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public QuerySection <T> From <T>(TableRelation <T> relation)
where T : Entity
{
//重新实例化一个Query
var query = new QuerySection <T>(relation.GetFromSection(), dbProvider, this);
//处理前n条
if (relation.GetTopSize() > 0)
{
query = query.GetTop(relation.GetTopSize());
}
return(query);
}
private FromSection <T> Join <TJoin>(TableRelation <TJoin> relation, string aliasName, WhereClip onWhere, JoinType joinType)
where TJoin : Entity
{
//将TableRelation的对象添加到当前节
this.entities.AddRange(relation.GetFromSection().TableEntities);
TJoin entity = CoreHelper.CreateInstance <TJoin>();
var table = entity.GetTable().As(aliasName);
if ((IField)query.PagingField == null)
{
//标识列和主键优先,包含ID的列被抛弃
query.SetPagingField(entity.PagingField);
}
string tableName = entity.GetTable().Name;
if (aliasName != null)
{
tableName = aliasName;
}
//处理tableRelation关系
string joinString = "(" + relation.GetFromSection().Query.QueryString + ") " + tableName;
this.query.Parameters = relation.GetFromSection().Query.Parameters;
string strJoin = string.Empty;
if (onWhere != null)
{
strJoin = " ON " + onWhere.ToString();
}
//获取关联方式
string join = GetJoinEnumString(joinType);
if (this.relation != null)
{
this.tableName = " __[[ " + this.tableName;
this.relation += " ]]__ ";
}
this.relation += join + joinString + strJoin;
return(this);
}
/// <summary>
/// 返回一个Query节
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public QuerySection <T> From <T>(TableRelation <T> relation)
where T : Entity
{
return(dbTrans.From <T>(relation));
}
/// <summary>
/// 右连接查询
/// </summary>
/// <typeparam name="TJoin"></typeparam>
/// <param name="relation"></param>
/// <param name="aliasName"></param>
/// <param name="onWhere"></param>
/// <returns></returns>
public FromSection <T> RightJoin <TJoin>(TableRelation <TJoin> relation, string aliasName, WhereClip onWhere)
where TJoin : Entity
{
return(Join <TJoin>(relation, aliasName, onWhere, JoinType.RightJoin));
}
/// <summary>
/// 右连接查询
/// </summary>
/// <typeparam name="TJoin"></typeparam>
/// <param name="relation"></param>
/// <param name="onWhere"></param>
/// <returns></returns>
public FromSection <T> RightJoin <TJoin>(TableRelation <TJoin> relation, WhereClip onWhere)
where TJoin : Entity
{
return(RightJoin(relation, null, onWhere));
}
