code: public SQLDialect determineSqlDialect(DataSource dataSource) {
  		if (this.sqlDialect != null) {
  			return this.sqlDialect;
  		}
  		return SqlDialectLookup.getDialect(dataSource);
  	}
docs: Determine the {@link SQLDialect} to use based on this configuration and the primary
  {@link DataSource}.
  @param dataSource the data source
  @return the {@code SQLDialect} to use for that {@link DataSource}