pkg database/sql/driver, type TxOptions struct, ReadOnly bool
pkg database/sql, func Named(string, interface{}) NamedArg
pkg database/sql, method (*ColumnType) DatabaseTypeName() string
pkg database/sql, method (*ColumnType) DecimalSize() (int64, int64, bool)
pkg database/sql, method (*ColumnType) Length() (int64, bool)
pkg database/sql, method (*ColumnType) Name() string
pkg database/sql, method (*ColumnType) Nullable() (bool, bool)

				if !field.PrimaryKey &&
					(len(matches2) == 1 && matches2[0][1] != fmt.Sprint(length) && ok) {
					alterColumn = true
				}
			}
		}

		// check precision
		if precision, _, ok := columnType.DecimalSize(); ok && int64(field.Precision) != precision {
			if regexp.MustCompile(fmt.Sprintf("[^0-9]%d[^0-9]", field.Precision)).MatchString(m.DataTypeOf(field)) {
				alterColumn = true
			}
		}
	}