Function extractTablesFromUpdate

backend/plugin/parser/mysql/backup.go:180–239

(databaseName string, n *ast.UpdateStmt, fullSQL string, offset int, dbMetadata *model.DatabaseMetadata)

}

func extractTablesFromUpdate(databaseName string, n *ast.UpdateStmt, fullSQL string, offset int, dbMetadata *model.DatabaseMetadata) ([]StatementInfo, error) {
	cteNames := collectCTENames(fullSQL, n.Loc)
	stmtText := extractStatementText(fullSQL, n.Loc)
	singleTables := collectSingleTables(databaseName, n.Tables)

	// Determine which tables are updated via SET clause column prefixes.
	updatedTables := make(map[string]bool)
	var unqualifiedColumns []string
	for _, assign := range n.SetList {
		if assign.Column != nil {
			table := assign.Column.Table
			if !cteNames[table] {
				updatedTables[table] = true
				if table == "" {
					unqualifiedColumns = append(unqualifiedColumns, assign.Column.Column)
				}
			}
		}
	}

	// Resolve unqualified columns using metadata.
	if updatedTables[""] {
		delete(updatedTables, "")
		resolved := resolveUnqualifiedColumns(unqualifiedColumns, singleTables, dbMetadata)
		for t := range resolved {
			updatedTables[t] = true
		}
	}

	// Single-table UPDATE (only one table, no explicit qualification needed).
	if len(updatedTables) == 0 && len(singleTables) == 1 {
		for _, ref := range singleTables {
			ref.StatementType = StatementTypeUpdate
			return []StatementInfo{{
				Offset:    offset,
				Statement: stmtText,
				Node:      n,
				Table:     ref,
				FullSQL:   fullSQL,
			}}, nil
		}
	}

	var result []StatementInfo
	for table := range updatedTables {
		ref, ok := singleTables[table]
		if !ok {
			return nil, errors.Errorf("cannot extract reference table: no matched updated table %q in referenced table list", table)
		}
		ref.StatementType = StatementTypeUpdate
		result = append(result, StatementInfo{
			Offset:    offset,
			Statement: stmtText,
			Node:      n,
			Table:     ref,
			FullSQL:   fullSQL,
		})
	}