/// <summary>
/// Adds a field
/// </summary>
public void AddField(string TableName, Field f)
{
lock(this.TableBlocking)// Total blocking required
{
string tbl = TableName;
QueryCacheDestroy(TableName);
Field[] flds = GetFields(TableName);
foreach(Field i in flds)
{
if(f.Name==i.Name)
throw new Exception("Column already present.");
}
//FieldsCache[TableName]=null; // cancel Field Cache
int tid = (int)this.TableName2TID[TableName];
TableNameDef tnd = this.TID2Def[tid] as TableNameDef;
try
{
// auto increment field seq
int fseq = tnd.fseq++;
this.fsDB.Position = tnd.PageOfTableDef * PageSize;
this.fsDB.Position += 1; // skip delete
this.fsDB.Position += 1; // skip type
this.fsDB.Position += 4; // skip fid
bw.Write( tnd.fseq );
bw.Flush();
// build page
int page = this.LockAvaiblePage();
this.fsDB.Position = page*PageSize;
bw.Write( (bool)true ); // deleted
bw.Flush();
bw.Write( (byte)FieldPageType );
bw.Write( tid );
f.seq=fseq;
f.tid=tid;
f.Write(bw);
bw.Flush();
f.PageOfFieldSef=page;
f.DataFID = new ArrayList();
this.fsDB.Position = page*PageSize;
bw.Write( (bool)false ); // active
bw.Flush();
tnd.fseq2FieldDef[f.seq]=f;
PeekPagesByFID(tid).Add(page);
// grow if it is needed
if(tnd.rownum>0)
{
int valSize = (int)f.DataSize();
long Capacity = (PageSize-ContentPageDataOffset)/valSize;
ArrayList pages = f.DataFID;
while((pages.Count*Capacity)<tnd.rownum)
{
int datapage = this.LockAvaiblePage();
bw.BaseStream.Position = (datapage*PageSize);
bw.Write( true );
bw.Flush();
bw.Write( (byte)Database.ContentPageType );
bw.Write( tnd.TableFID );
bw.Write( (int)f.seq );
bw.Write( f.DataFID.Count );
bw.Flush();
for(int c=0;c<Capacity;c++)
{
bw.BaseStream.Position = (datapage*PageSize)+ContentPageDataOffset+c*valSize;
f.WriteDefaultData(bw,false);
}
bw.Flush();
bw.BaseStream.Position = (datapage*PageSize);
bw.Write( (bool)false );
bw.Flush();
pages.Add(datapage);
PeekPagesByFID(tid).Add(datapage);
this.InvalidatePage(datapage);
}
}
}
catch(Exception ex)
{
this.LogToFile(ex.Message,ex.StackTrace);
throw new Exception("Unhandled exception at AddField.");
}
}
}
