/// <summary>
/// Alters the column.
/// </summary>
/// <param name="databaseTable">The database table.</param><param name="databaseColumn">The database column.</param><param name="originalColumn">The original column.</param>
/// <returns/>
public override string AlterColumn(DatabaseTable databaseTable, DatabaseColumn databaseColumn, DatabaseColumn originalColumn)
{
var tableGenerator = CreateTableGenerator(databaseTable);
if (!AlterColumnIncludeDefaultValue)
{
tableGenerator.IncludeDefaultValues = false;
}
var columnDefinition = tableGenerator.WriteColumn(databaseColumn).Trim();
var originalDefinition = "?";
if (originalColumn != null)
{
originalDefinition = tableGenerator.WriteColumn(originalColumn).Trim();
}
//add a nice comment
var comment = string.Format(CultureInfo.InvariantCulture,
"-- {0} from {1} to {2}",
databaseTable.Name,
originalDefinition,
columnDefinition);
if (!SupportsAlterColumn)
{
//SQLite does not have modify column
return(comment + Environment.NewLine + "-- TODO: change manually (no ALTER COLUMN)");
}
if (databaseColumn.IsPrimaryKey || databaseColumn.IsForeignKey)
{
//you can't change primary keys
//you can't change foreign key columns
return(comment + Environment.NewLine + "-- TODO: change manually (PK or FK)");
}
var dtw = new DataTypeWriter();
var dataType = dtw.WriteDataType(databaseColumn);
var columnDef = Escape(databaseColumn.Name) + " TYPE " +
dataType.TrimEnd();
return(comment +
Environment.NewLine +
string.Format(CultureInfo.InvariantCulture,
AlterColumnFormat,
TableName(databaseTable),
columnDef.Replace("NOT NULL", String.Empty)) +
string.Format("\r\nALTER TABLE {0} ALTER COLUMN {1} {2} NOT NULL;",
TableName(databaseTable), Escape(databaseColumn.Name), (databaseColumn.Nullable ? "DROP" : "SET")));
}
public TableGenerator(DatabaseTable table)
: base(table)
{
DataTypeWriter = new DataTypeWriter();
}
