60 lines
1.9 KiB
Go
60 lines
1.9 KiB
Go
package migration
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import (
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"context"
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"fmt"
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"strings"
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)
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func ensureIndex(ctx context.Context, exec executor, dialect Dialect, table, index string, unique bool, columns []string) error {
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exists, err := indexExists(ctx, exec, dialect, table, index)
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if err != nil {
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return fmt.Errorf("check index %s: %w", index, err)
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}
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if exists {
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return nil
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}
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quotedTable, quotedIndex, err := quotedIdentifiers(dialect, table, index)
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if err != nil {
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return err
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}
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quotedColumns := make([]string, 0, len(columns))
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for _, column := range columns {
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_, quotedColumn, err := quotedIdentifiers(dialect, table, column)
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if err != nil {
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return err
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}
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quotedColumns = append(quotedColumns, quotedColumn)
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}
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indexType := "INDEX"
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if unique {
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indexType = "UNIQUE INDEX"
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}
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statement := fmt.Sprintf("CREATE %s %s ON %s (%s)", indexType, quotedIndex, quotedTable, strings.Join(quotedColumns, ", "))
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if _, err := exec.ExecContext(ctx, statement); err != nil {
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return fmt.Errorf("create index %s: %w", index, err)
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}
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return nil
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}
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func indexExists(ctx context.Context, exec executor, dialect Dialect, table, index string) (bool, error) {
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var count int
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switch dialect {
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case DialectSQLite:
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if err := exec.QueryRowContext(ctx, `SELECT COUNT(*) FROM pragma_index_list(?) WHERE name = ?`, table, index).Scan(&count); err != nil {
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return false, err
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}
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case DialectMySQL:
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if err := exec.QueryRowContext(ctx, "SELECT COUNT(*) FROM information_schema.statistics WHERE table_schema = DATABASE() AND table_name = ? AND index_name = ?", table, index).Scan(&count); err != nil {
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return false, err
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}
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case DialectPostgres:
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if err := exec.QueryRowContext(ctx, "SELECT COUNT(*) FROM pg_indexes WHERE schemaname = current_schema() AND tablename = $1 AND indexname = $2", table, index).Scan(&count); err != nil {
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return false, err
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}
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default:
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return false, fmt.Errorf("unsupported index dialect %q", dialect)
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}
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return count > 0, nil
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}
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