public static void AssertColumnDeleteAllowed(this MigrationOptions opts, string table, string column, string field)
{
opts.AssertNotFrozen($"change '{field}' of '{column}' of '{table}'");
if (!opts.AllowDataloss)
{
throw new InvalidOperationException($"Can't migrate column '{column}' of '{table}', {field} can't be changed without dataloss");
}
}
public static void AssertColumnDeleteAllowed(this MigrationOptions opts, string table, string column)
{
opts.AssertNotFrozen($"delete '{column}' of '{table}'");
if (!opts.AllowDataloss)
{
throw new InvalidOperationException($"Can't delete column '{column}' of '{table}', dataloss is not allowed");
}
}
protected void PlanMigrateColumn(SchemaMigrationPlan report, ColumnSchema existing, ColumnSchema target, MigrationOptions options)
{
if (existing == null)
{
if (target.KeyIndex > 0)
{
throw new InvalidOperationException($"Cannot migrate column {target.Name} of {report.Target.Name}, keys can't be changed");
}
options.AssertNotFrozen($"Create column {target.Name} of {report.Target.Name}");
report.Steps.Add(new MigrationStep()
{
TargetName = target.Name,
Action = MigrationAction.Create,
TargetType = MigrationTarget.Column,
});
return;
}
if (target == null)
{
if (existing.KeyIndex > 0)
{
throw new InvalidOperationException($"Cannot migrate column {existing.Name} of {report.Target.Name}, keys can't be changed");
}
options.AssertColumnDeleteAllowed(report.Target.Name, existing.Name);
report.Steps.Add(new MigrationStep()
{
TargetName = existing.Name,
Action = MigrationAction.Drop,
TargetType = MigrationTarget.Column,
});
return;
}
bool mismatched = false;
if (target.KeyIndex != existing.KeyIndex)
{
throw new InvalidOperationException($"Cannot migrate column {target.Name} of {report.Target.Name}, keys can't be changed");
}
if (target.SqlType != existing.SqlType)
{
mismatched = true;
options.AssertColumnDeleteAllowed(report.Target.Name, target.Name, "type");
}
if (target.Nullable != existing.Nullable)
{
mismatched = true;
options.AssertColumnDeleteAllowed(report.Target.Name, target.Name, "nullable");
}
if (target.MaxLength != existing.MaxLength)
{
mismatched = true;
options.AssertColumnDeleteAllowed(report.Target.Name, target.Name, "maxlength");
}
if (mismatched)
{
options.AssertColumnDeleteAllowed(report.Target.Name, target.Name);
report.Steps.Add(new MigrationStep()
{
TargetName = target.Name,
Action = MigrationAction.Drop,
TargetType = MigrationTarget.Column,
});
report.Steps.Add(new MigrationStep()
{
TargetName = target.Name,
Action = MigrationAction.Create,
TargetType = MigrationTarget.Column,
});
return;
}
}