/// <summary>
/// 计算出两个数据库元数据的所有表差别
/// </summary>
/// <param name="oldDatabase">旧数据库</param>
/// <param name="newDatabase">新数据库</param>
/// <returns></returns>
public static DatabaseChanges Distinguish(Database oldDatabase, DestinationDatabase newDatabase)
{
if (!oldDatabase.Removed)
{
oldDatabase.OrderByRelations();
}
if (!newDatabase.Removed)
{
newDatabase.OrderByRelations();
}
List <TableChanges> result = new List <TableChanges>();
if (!oldDatabase.Removed && !newDatabase.Removed)
{
//先找出所有被删除的表
foreach (var oldTable in oldDatabase.Tables.Reverse())
{
if (newDatabase.FindTable(oldTable.Name) == null && !newDatabase.IsIgnored(oldTable.Name))
{
result.Add(new TableChanges(oldTable, null, ChangeType.Removed));
}
}
foreach (var newTable in newDatabase.Tables)
{
if (!newDatabase.IsIgnored(newTable.Name))
{
var oldTable = oldDatabase.FindTable(newTable.Name);
//如果没有找到旧表，说明这个表是新加的。
if (oldTable == null)
{
result.Add(new TableChanges(null, newTable, ChangeType.Added));
}
else
{
//即不是新表，也不是旧表，计算两个表的区别
TableChanges record = Distinguish(oldTable, newTable);
//如果有区别，则记录下来
if (record != null)
{
result.Add(record);
}
}
}
}
}
return(new DatabaseChanges(oldDatabase, newDatabase, result));
}
/// <summary>
/// 计算出新旧表之间的数据列差别
/// </summary>
/// <param name="oldTable">旧表</param>
/// <param name="newTable">新表</param>
/// <returns>
/// 返回表之间区别，如果没有区别，则返回null
/// </returns>
private static TableChanges Distinguish(Table oldTable, Table newTable)
{
//if (newTable == null) throw new ArgumentNullException("newTable");
//if (oldTable == null) throw new ArgumentNullException("oldTable");
//if (newTable.Name != oldTable.Name) throw new InvalidOperationException("newTable.Name != oldTable.Name must be false.");
var record = new TableChanges(oldTable, newTable, ChangeType.Modified);
//先找到已经删除的列
foreach (var oldColumn in oldTable.Columns)
{
if (newTable.FindColumn(oldColumn.Name) == null)
{
record.ColumnsChanged.Add(new ColumnChanges(oldColumn, null, ChangeType.Removed));
}
}
//记录新增的和更改过的列
foreach (var column in newTable.Columns)
{
Column oldColumn = oldTable.FindColumn(column.Name);
if (oldColumn == null)
{
var columnChanged = new ColumnChanges(null, column, ChangeType.Added);
record.ColumnsChanged.Add(columnChanged);
}
else
{
var columnChanged = Distinguish(oldColumn, column);
//新增的 或者 修改的 列
if (columnChanged != null)
{
record.ColumnsChanged.Add(columnChanged);
}
}
}
//如果被修改了，则返回record；否则返回null
if (record.ColumnsChanged.Count > 0)
{
return(record);
}
return(null);
}
/// <summary>
/// 计算出新旧表之间的数据列差别
/// </summary>
/// <param name="oldTable">旧表</param>
/// <param name="newTable">新表</param>
/// <returns>
/// 返回表之间区别，如果没有区别，则返回null
/// </returns>
private static TableChanges Distinguish(Table oldTable, Table newTable)
{
//if (newTable == null) throw new ArgumentNullException("newTable");
//if (oldTable == null) throw new ArgumentNullException("oldTable");
//if (newTable.Name != oldTable.Name) throw new InvalidOperationException("newTable.Name != oldTable.Name must be false.");
var record = new TableChanges(oldTable, newTable, ChangeType.Modified);
//先找到已经删除的列
foreach (var oldColumn in oldTable.Columns)
{
if (newTable.FindColumn(oldColumn.Name) == null)
{
record.ColumnsChanged.Add(new ColumnChanges(oldColumn, null, ChangeType.Removed));
}
}
//记录新增的和更改过的列
foreach (var column in newTable.Columns)
{
Column oldColumn = oldTable.FindColumn(column.Name);
if (oldColumn == null)
{
var columnChanged = new ColumnChanges(null, column, ChangeType.Added);
record.ColumnsChanged.Add(columnChanged);
}
else
{
var columnChanged = Distinguish(oldColumn, column);
//新增的 或者 修改的 列
if (columnChanged != null) { record.ColumnsChanged.Add(columnChanged); }
}
}
//如果被修改了，则返回record；否则返回null
if (record.ColumnsChanged.Count > 0) { return record; }
return null;
}
private void GenerateOpertions(TableChanges tableChanges)
{
switch (tableChanges.ChangeType)
{
case ChangeType.Added:
this.AddTable(tableChanges.NewTable);
break;
case ChangeType.Removed:
this.RemoveTable(tableChanges.OldTable);
break;
case ChangeType.Modified:
foreach (var column in tableChanges.ColumnsChanged)
{
this.GenerateOpertions(column);
}
break;
default:
break;
}
}
