/// <summary>
/// 利用DbColumn的信息，去除匹配到相同列的多余属性，只选择其中一个。选择的规定为：
/// 1、当只有一个属性匹配时，则选择之；
/// 2、当有多个属性匹配，则深度不同时，选择深度最小者。
/// 如A.B.C.D, A.B.D。则选择后者
/// 3、如果有多个属性匹配，且最小深度有多个，则默认选择第一个。
/// </summary>
/// <returns></returns>
private IList <DBColumnMapping> DeduplicateDbColumnMappingByOffset(IList <LeafPropertyNode> leafs)
{
var filtered = new List <DBColumnMapping>();
foreach (var group in leafs
.SelectMany(l => l.DbColumnMappings)
.GroupBy(m => m.DestColumnOffset))
{
//规则一
if (group.Count() == 1)
{
filtered.Add(group.First());
}
else
{
//规则二、三
DBColumnMapping selected = group.OrderBy(t => t.Host.Depth * 10 + (int)t.Option).First();
filtered.Add(selected);
foreach (var mapping in group)
{
if (!object.ReferenceEquals(mapping, selected))
{
m_classLogger.WarnFormat("Column mapping {0} on {1} abandoned as its offset {2} is already used by {3}", mapping, mapping.Host, mapping.DestColumnOffset, selected);
}
}
}
}
return(filtered);
}
public int GetColumnOffset(string name)
{
DBColumnMapping columnAttr =
m_dbColumnMappings.FirstOrDefault(
col => string.Equals(col.DestColumnName, name, StringComparison.OrdinalIgnoreCase));
return(columnAttr == null ? -1 : columnAttr.DestColumnOffset);
}
private void AutoCreateDBColumnMapping(IList <LeafPropertyNode> leafNodes)
{
//there isn't property with DestLabel attribute,so we can get it from database table.
LogHelper.Logger.WarnFormat(
"Mapping property by schema table for current type: {0}, which has no attribute on each of its properties.",
typeof(T));
#region 没有属性存在DbColumnMapping。因此，采用属性名称匹配数据库
DataTable dataTable = this.SchemaTable;
foreach (DataColumn column in dataTable.Columns)
{
if (column == null || column.ReadOnly)
{
continue;
}
IEnumerable <LeafPropertyNode> matchedLeafs =
leafNodes.Where(
t => string.Equals(t.PropertyInfo.Name, column.ColumnName, StringComparison.OrdinalIgnoreCase));
foreach (LeafPropertyNode leaf in matchedLeafs)
{
var dbMapping = new DBColumnMapping(this.m_destLabel, column.Ordinal, null)
{
DestColumnName = column.ColumnName
};
dbMapping.Host = leaf;
leaf.DbColumnMappings.Add(dbMapping);
}
}
#endregion
}
public InvalidDBColumnMappingException(string description, DBColumnMapping mapping, LeafPropertyNode node) : base()
{
this.m_description = description;
this.m_mapping = mapping;
this.m_node = node;
}
/// <summary>
/// Register an external mapping to affect the column mapping process by type accessors.
/// </summary>
/// <typeparam name="T">Type of the root object</typeparam>
/// <typeparam name="TValue">Return type of the leaf property</typeparam>
/// <param name="propertyPath">A lambda expression which defines the property path from root type to the leaf property</param>
/// <param name="mapping">The mapping to register to the give property path</param>
public static void RegisterMapping <T, TValue>(Expression <Func <T, TValue> > propertyPath, DBColumnMapping mapping) where T : class
{
//todo: add lambda expression check
RegisterMapping(propertyPath.Body, mapping);
}
public string GetName(int columnOffset)
{
DBColumnMapping columnAttr = m_dbColumnMappings.FirstOrDefault(col => col.DestColumnOffset == columnOffset);
return(columnAttr == null ? null : columnAttr.DestColumnName);
}
private static void RegisterMapping(Expression propertyPath, DBColumnMapping mapping)
{
s_externalMappings.Add(Tuple.Create(propertyPath, mapping));
}
/// <summary>
/// 说明：此方法用于利用数据库表的列字段的：位置或名称，将DbColumnMapping补全。
/// 如果输入的propertyInfo.PropertyType不是“原子类型”或“String”，显然在数据库中不会有匹配的列；所以直接返回
/// </summary>
/// <param name="propertyInfo"></param>
/// <param name="mapping"></param>
private void PopulateDbColumnMapping(LeafPropertyNode leaf, DBColumnMapping mapping)
{
DataTable schemaTable = this.SchemaTable;
if (mapping.IsDestColumnNameOk() && mapping.IsDestColumnOffsetOk())
{
DataColumn col = schemaTable.Columns[mapping.DestColumnOffset];
if (col == null)
{
if (mapping.Option == ColumnMappingOption.Optional)
{
m_classLogger.DebugFormat("Optional column mapping ignored for table {0}: {1}", m_destinationTablename, mapping);
mapping.DestColumnOffset = -1;
return;
}
else
{
var desc = string.Format(
"can not find column with offset {0} in table {1} ",
mapping.DestColumnOffset,
m_destinationTablename);
throw new InvalidDBColumnMappingException(desc, mapping, leaf);
}
}
if (col.ColumnName != mapping.DestColumnName)
{
var desc = string.Format(
"Column name from db {0} is inconsistent with that in db mapping {1} ",
col.ColumnName,
mapping);
throw new InvalidDBColumnMappingException(desc, mapping, leaf);
}
return;
}
//说明当前的mapping的列名称出错（null），而位置参数正确。则读取数据库表获得要相应的列名称
if (!mapping.IsDestColumnNameOk() && mapping.IsDestColumnOffsetOk())
{
DataColumn col = schemaTable.Columns[mapping.DestColumnOffset];
if (col == null)
{
if (mapping.Option == ColumnMappingOption.Optional)
{
m_classLogger.DebugFormat("Optional column mapping ignored for table {0}: {1}", m_destinationTablename, mapping);
mapping.DestColumnOffset = -1;
return;
}
else
{
var desc = string.Format(
"can not find column with offset {0} in table {1} ",
mapping.DestColumnOffset,
m_destinationTablename);
throw new InvalidDBColumnMappingException(desc, mapping, leaf);
}
}
mapping.DestColumnName = col.ColumnName;
this.m_classLogger.DebugFormat("Populated column name for DBColumnMapping: {0} on property node: {1} by table {2}",
mapping,
leaf,
m_destinationTablename);
return;
}
//说明当前的mapping的列名称存在，而位置参数出错（-1）。则读取数据库表获得相应的列位置参数
if (mapping.IsDestColumnNameOk() && !mapping.IsDestColumnOffsetOk())
{
DataColumn col = schemaTable.Columns[mapping.DestColumnName];
if (col == null)
{
if (mapping.Option == ColumnMappingOption.Optional)
{
m_classLogger.DebugFormat(
"Optional column mapping ignored for table {0}: {1}",
m_destinationTablename,
mapping);
mapping.DestColumnOffset = -1;
return;
}
else
{
var desc = string.Format(
"can not find column with name {0} in table {1} ",
mapping.DestColumnName,
m_destinationTablename);
throw new InvalidDBColumnMappingException(desc, mapping, leaf);
}
}
mapping.DestColumnOffset = col.Ordinal;
this.m_classLogger.DebugFormat("Populated column offset for DBColumnMapping: {0} on property node: {1} by table {2}",
mapping,
leaf,
m_destinationTablename);
return;
}
//说明当前的mapping列名称不存在，位置参数也不存在，因此，根据PropertyInfo.Name读取数据库
DataColumn guessColumn = schemaTable.Columns[leaf.PropertyInfo.Name];
if (guessColumn == null)
{
if (mapping.Option == ColumnMappingOption.Optional)
{
m_classLogger.DebugFormat("Optional column mapping ignored for table {0}: {1}", m_destinationTablename, mapping);
mapping.DestColumnOffset = -1;
return;
}
else
{
var desc = string.Format(
"can not find column with property name {0} in table {1} ",
leaf.PropertyInfo.Name,
m_destinationTablename);
throw new InvalidDBColumnMappingException(desc, mapping, leaf);
}
}
mapping.DestColumnOffset = guessColumn.Ordinal;
mapping.DestColumnName = guessColumn.ColumnName;
this.m_classLogger.DebugFormat("Populated column name and offset for DBColumnMapping: {0} on property node: {1} by table {2}",
mapping,
leaf,
m_destinationTablename);
}
