/// <summary>
/// Internal Extendable method: 创建实体对象
/// </summary>
/// <param name="objectAccessor">实体对象访问器</param>
/// <param name="tableMapper">Table元数据解析器</param>
/// <param name="reader">数据流</param>
/// <param name="columnNames">查询结果列的数组</param>
/// <returns>实体对象</returns>
internal static object CreateEntity(this ObjectAccessor objectAccessor, ITableMapper tableMapper, IDataReader reader, string[] columnNames)
{
//创建对象
object entity = objectAccessor.CreateInstance();
//读取DataReader当前行,为entity各个属性赋值
objectAccessor.Fill(tableMapper.GetColumnMappers(), reader, columnNames, entity);
//返回对象
return(entity);
}
/// <summary>
/// 创建表
/// </summary>
/// <param name="dbHelper">操作数据库的Helper</param>
/// <param name="commandTreeFactory">创建CommandTree的工厂</param>
/// <param name="tableMapper">Table元数据解析器</param>
public int CreateTable(DbHelper dbHelper, ICommandTreeFactory commandTreeFactory, ITableMapper tableMapper)
{
//获取TableHeader
ITableHeader tableHeader = tableMapper.Header;
//获取ColumnNodes
IEnumerable <IColumnNode> columnNodes = tableMapper.GetColumnMappers().Select(m => m.ToColumnNode());
//获取建表语句生成树
ICommandTree buildTableTree = commandTreeFactory.GetBuildTableTree(tableHeader.SchemaName, tableHeader.TableName, columnNodes);
//创建建表语句并执行
return(dbHelper.ExecuteUpdate(buildTableTree.Compile()));
}
/// <summary>
/// 为当前实体所Mapping的Table添加没有添加的列
/// </summary>
/// <param name="dbHelper">操作数据库的Helper对象</param>
/// <param name="commandTreeFactory">创建CommandTree的工厂</param>
/// <param name="tableMapper">Table元数据解析器</param>
public void AlterTableAddColumns(DbHelper dbHelper, ICommandTreeFactory commandTreeFactory, ITableMapper tableMapper)
{
//获取当前实体元数据解析器中某些属性Mapping的Column未包含在Table中的属性对应的ColumnMapper,并转换获取Column节点
string[] columnNames = this.GetColumns(dbHelper, tableMapper.Header).ToArray();
IColumnNode[] columnNodes = (from columnMapper
in tableMapper.GetColumnMappers()
where !columnNames.Contains(columnMapper.ColumnName)
select columnMapper.ToColumnNode()).ToArray();
//若实体元数据解析器中所有属性Mapping的列都在当前Table中,直接退出
if (columnNodes.Length == 0)
{
return;
}
//获取TableHeader
ITableHeader tableHeader = tableMapper.Header;
//创建Alter Table Columns语句生成树
ICommandTree alterTableAddColumnsTree = commandTreeFactory.GetAlterTableAddColumnsTree(tableHeader.SchemaName, tableHeader.TableName, columnNodes);
//生成并执行Alter Table Columns语句，为当前实体Mapping的Table添加为注册的列
dbHelper.ExecuteUpdate(alterTableAddColumnsTree.Compile());
}