/// <summary>Add a new column to the DB.</summary>
/// <remarks>
/// <para>The column must exist in the record's type.</para>
/// <para>If you're creating a column that's no longer in the schema (because you're doing a sequential upgrade step to the non-latest version),
/// you better leave the column + attribute in the record class, but mark it with <see cref="System.ObsoleteAttribute">[Obsolete]</see> attribute.</para>
/// </remarks>
/// <typeparam name="tRow">Record type</typeparam>
/// <param name="name">Name of the ESENT column to add</param>
public void AddColumn <tRow>(string name) where tRow : new()
{
TypeSerializer ser = serializerForType(typeof(tRow));
TypeSerializer.ColumnInfo ci = ser.getColumnsSchema().FirstOrDefault(c => c.columnName == name);
if (null == ci)
{
throw new SerializationException("The column '" + name + "' was not found on row type '" + typeof(tRow).Name + "'.");
}
Action act = () =>
{
JET_TABLEID idTable;
Api.JetOpenTable(this.session.idSession, this.session.idDatabase, ser.tableName, null, 0, OpenTableGrbit.None, out idTable);
try
{
JET_COLUMNID idColumn;
Api.JetAddColumn(this.session.idSession, idTable, ci.columnName, ci.attrib.getColumnDef(), null, 0, out idColumn);
if (!ci.attrib.bFieldNullable)
{
// The new column is not nullable.
// It means attempts to de-serialize the column will throw saying "Nullable object must have a value"
// To fix, we update all records of the table, setting the default value of the column.
// TODO: instead of creating default value for type, use reflection to find out is there a default value in the record class
object objVal = Activator.CreateInstance(ci.tpValue);
Cursor <tRow> cur = new Cursor <tRow>(this.session, ser, idTable, false);
if (cur.TryMoveFirst())
{
do
{
cur.SaveSingleField(ci.columnName, objVal);
// TODO [low]: pulse the transaction here.. The version store can be exhausted for large tables.
}while(cur.tryMoveNext());
}
}
}
finally
{
Api.JetCloseTable(this.session.idSession, idTable);
}
};
this.actUpgrade += act;
}
int Import(TextReader tr)
{
string line;
// Header; we also trim that extra trailing tabs being appended by Excel when saving documents in the TSV format.
line = tr.ReadLine().TrimEnd(s_cTab);
if (line != this.GetType().FullName)
{
throw new SerializationException("Wrong signature: stored " + line + ", must be " + this.GetType().FullName + ".");
}
line = tr.ReadLine().TrimEnd(s_cTab);
int cols = int.Parse(line);
if (schema.Count != cols)
{
throw new SerializationException("Wrong columns count: stored " + cols + ", must be " + schema.Count + ".");
}
// Validate the stored columns schema.
JET_COLUMNDEF[] arrCd = new JET_COLUMNDEF[cols];
string[] arr;
for (int i = 0; i < cols; i++)
{
TypeSerializer.ColumnInfo ci = schema[i];
JET_COLUMNDEF cd = ci.attrib.getColumnDef();
arrCd[i] = cd;
line = tr.ReadLine();
arr = line.Split(new char[] { '\t' });
if (arr[0] != ci.columnName)
{
throw new SerializationException("Wrong column name: stored '" + arr[0] + "', must be '" + ci.columnName + "'.");
}
eColumnKind ck = (eColumnKind)(Enum.Parse(typeof(eColumnKind), arr[1]));
if (ck != ci.attrib.getColumnKind())
{
throw new SerializationException("Wrong column kind: stored '" + ck.ToString() + "', must be '" + ci.attrib.getColumnKind().ToString() + "'.");
}
if (cd.coltyp != (JET_coltyp)(int.Parse(arr[2])))
{
throw new SerializationException("Mismatched type of column '" + ci.columnName + "'");
}
if (cd.cp != (JET_CP)(int.Parse(arr[3])))
{
throw new SerializationException("Mismatched codepage of column '" + ci.columnName + "'");
}
if (cd.grbit != (ColumndefGrbit)(int.Parse(arr[4])))
{
throw new SerializationException("Mismatched bit flags of column '" + ci.columnName + "'");
}
}
// Import the rows.
return(ImportData
(
( int nRecord ) =>
{
line = tr.ReadLine();
return line != null;
},
( int nRecord ) =>
{
if (line == "")
{
return false;
}
arr = line.Split(s_cTab);
if (arr.Length < cols)
{
throw new SerializationException("Too few columns in the line '" + line + "'");
}
for (int i = 0; i < cols; i++)
{
JET_COLUMNDEF cd = arrCd[i];
if (0 != (cd.grbit & ColumndefGrbit.ColumnAutoincrement))
{
// TODO: look for a way to restore ColumnAutoincrement values.
continue;
}
if (!isMultiValued(cd))
{
LoadVal(arr[i], schema[i].idColumn, cd.coltyp, cd.cp);
}
else
{
string[] arr2 = arr[i].Split(s_cSlash);
foreach (string item in arr2)
{
LoadVal(item, schema[i].idColumn, cd.coltyp, cd.cp);
}
}
}
return true;
}
));
}
int Export(TextWriter tw)
{
int cols = schema.Count;
// Header
tw.WriteLine(this.GetType().FullName);
tw.WriteLine(cols);
// Columns schema
JET_COLUMNDEF[] arrCd = new JET_COLUMNDEF[cols];
string[] arr;
for (int i = 0; i < cols; i++)
{
TypeSerializer.ColumnInfo ci = schema[i];
JET_COLUMNDEF cd = ci.attrib.getColumnDef();
arrCd[i] = cd;
arr = new string[]
{
ci.columnName,
ci.attrib.getColumnKind().ToString(),
((int)cd.coltyp).ToString(),
((int)cd.cp).ToString(),
((int)cd.grbit).ToString(),
};
tw.WriteLine(string.Join("\t", arr));
}
// Rows
arr = new string[cols];
return(ExportData
(
( int nRecord ) =>
{
for (int i = 0; i < cols; i++)
{
JET_COLUMNDEF cd = arrCd[i];
if (isMultiValued(cd))
{
for (int j = 1; true; j++)
{
string val = getStringValue(tw, schema[i].idColumn, j, cd.coltyp, cd.cp);
if (val == "")
{
break;
}
if (j > 1)
{
tw.Write('/');
}
tw.Write(val);
}
}
else
{
string val = getStringValue(tw, schema[i].idColumn, 1, cd.coltyp, cd.cp);
tw.Write(val);
}
if (i + 1 < cols)
{
tw.Write('\t');
}
}
tw.WriteLine();
}
));
}