Golang TableDescriptor.Renames方法代碼示例

//.........這裏部分代碼省略.........
			return nil, sqlbase.NewUndefinedViewError(oldTn.String())
		}
	} else {
		tableDesc, err = p.getTableDesc(oldTn)
		if err != nil {
			return nil, err
		}
		if tableDesc == nil {
			if n.IfExists {
				// Noop.
				return &emptyNode{}, nil
			}
			// Key does not exist, but we want it to: error out.
			return nil, sqlbase.NewUndefinedTableError(oldTn.String())
		}
		if tableDesc.State != sqlbase.TableDescriptor_PUBLIC {
			return nil, sqlbase.NewUndefinedTableError(oldTn.String())
		}
	}

	if err := p.checkPrivilege(tableDesc, privilege.DROP); err != nil {
		return nil, err
	}

	// Check if any views depend on this table/view. Because our views
	// are currently just stored as strings, they explicitly specify the name
	// of everything they depend on. Rather than trying to rewrite the view's
	// query with the new name, we simply disallow such renames for now.
	if len(tableDesc.DependedOnBy) > 0 {
		return nil, p.dependentViewRenameError(
			tableDesc.TypeName(), oldTn.String(), tableDesc.ParentID, tableDesc.DependedOnBy[0].ID)
	}

	// Check if target database exists.
	targetDbDesc, err := p.mustGetDatabaseDesc(newTn.Database())
	if err != nil {
		return nil, err
	}

	if err := p.checkPrivilege(targetDbDesc, privilege.CREATE); err != nil {
		return nil, err
	}

	// oldTn and newTn are already normalized, so we can compare directly here.
	if oldTn.Database() == newTn.Database() && oldTn.Table() == newTn.Table() {
		// Noop.
		return &emptyNode{}, nil
	}

	tableDesc.SetName(newTn.Table())
	tableDesc.ParentID = targetDbDesc.ID

	descKey := sqlbase.MakeDescMetadataKey(tableDesc.GetID())
	newTbKey := tableKey{targetDbDesc.ID, newTn.Table()}.Key()

	if err := tableDesc.Validate(p.txn); err != nil {
		return nil, err
	}

	descID := tableDesc.GetID()
	descDesc := sqlbase.WrapDescriptor(tableDesc)

	if err := tableDesc.SetUpVersion(); err != nil {
		return nil, err
	}
	renameDetails := sqlbase.TableDescriptor_RenameInfo{
		OldParentID: dbDesc.ID,
		OldName:     oldTn.Table()}
	tableDesc.Renames = append(tableDesc.Renames, renameDetails)
	if err := p.writeTableDesc(tableDesc); err != nil {
		return nil, err
	}

	// We update the descriptor to the new name, but also leave the mapping of the
	// old name to the id, so that the name is not reused until the schema changer
	// has made sure it's not in use any more.
	b := &client.Batch{}
	b.Put(descKey, descDesc)
	b.CPut(newTbKey, descID, nil)

	if err := p.txn.Run(b); err != nil {
		if _, ok := err.(*roachpb.ConditionFailedError); ok {
			return nil, sqlbase.NewRelationAlreadyExistsError(newTn.Table())
		}
		return nil, err
	}
	p.notifySchemaChange(tableDesc.ID, sqlbase.InvalidMutationID)

	p.setTestingVerifyMetadata(func(systemConfig config.SystemConfig) error {
		if err := expectDescriptorID(systemConfig, newTbKey, descID); err != nil {
			return err
		}
		if err := expectDescriptor(systemConfig, descKey, descDesc); err != nil {
			return err
		}
		return nil
	})

	return &emptyNode{}, nil
}