private FromSection <T> Join <TJoin>(Table table, WhereClip onWhere, JoinType joinType)
where TJoin : Entity
{
TJoin entity = DataUtils.CreateInstance <TJoin>();
this.entityList.Add(entity);
if ((IField)query.PagingField == null)
{
//标识列和主键优先,包含ID的列被抛弃
query.PagingField = entity.PagingField;
}
FromSection <TJoin> from = new FromSection <TJoin>(table);
string strJoin = string.Empty;
if (onWhere != null)
{
strJoin = " on " + onWhere.ToString();
}
string join = GetJoinEnumString(joinType);
if (this.relation != null)
{
this.tableName = " {2} " + this.tableName;
this.relation += " {3} ";
}
this.relation += join + from.TableName + strJoin;
return(this);
}
internal QuerySection(FromSection <T> fromSection, DbProvider dbProvider, DbTrans dbTran, Field pagingField)
{
this.fromSection = fromSection;
this.dbProvider = dbProvider;
this.dbTran = dbTran;
this.pagingField = pagingField;
}
/// <summary>
/// 返回一个Query节
/// </summary>
/// <returns></returns>
public QuerySection From(QueryCreator creator)
{
if (creator.Table == null)
{
throw new DataException("用创建器操作时，表不能为null！");
}
FromSection <ViewEntity> f = this.From <ViewEntity>(creator.Table);
if (creator.IsRelation)
{
foreach (TableJoin join in creator.Relations.Values)
{
if (join.Type == JoinType.LeftJoin)
{
f.LeftJoin <ViewEntity>(join.Table, join.Where);
}
else if (join.Type == JoinType.RightJoin)
{
f.RightJoin <ViewEntity>(join.Table, join.Where);
}
else
{
f.InnerJoin <ViewEntity>(join.Table, join.Where);
}
}
}
QuerySection <ViewEntity> query = f.Select(creator.Fields).Where(creator.Where)
.OrderBy(creator.OrderBy);
return(new QuerySection(query));
}
/// <summary>
/// 判断记录是否存在
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="table"></param>
/// <param name="entity"></param>
/// <returns></returns>
private bool Exists <T>(Table table, T entity)
where T : Entity
{
WhereClip where = DataUtils.GetPkWhere <T>(table, entity);
FromSection <T> fs = new FromSection <T>(dbProvider, dbTrans, table);
return(fs.Where(where).Count() > 0);
}
/// <summary>
/// 判断记录是否存在
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="table"></param>
/// <param name="where"></param>
/// <returns></returns>
private bool Exists <T>(Table table, WhereClip where)
where T : Entity
{
if (where == null || where == WhereClip.None)
{
throw new DataException("在判断记录是否存在时出现异常，条件为null或WhereClip.None！");
}
FromSection <T> fs = new FromSection <T>(dbProvider, dbTrans, table, null);
return(fs.Where(where).Count() > 0);
}
/// <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);
}
internal TableRelation(Table table)
{
if (table == null)
{
this.section = new FromSection <T>(null, null, Table.GetTable <T>());
}
else
{
this.section = new FromSection <T>(null, null, table);
}
this.section.EntityList.Add(DataUtils.CreateInstance <T>());
}
internal QuerySection(FromSection <T> fromSection)
{
this.fromSection = fromSection;
}
internal TopSection(string topString, FromSection <T> fromSection, DbProvider dbProvider, DbTrans dbTran, Field pagingField, int topSize)
: base(fromSection, dbProvider, dbTran, pagingField)
{
this.topString = topString;
this.topSize = topSize;
}
internal QuerySection(FromSection <T> fromSection, DbProvider dbProvider, DbTrans dbTran)
{
this.fromSection = fromSection;
this.dbProvider = dbProvider;
this.dbTran = dbTran;
}
