content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to you under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.calcite.test;
  
  import org.apache.calcite.DataContexts;
  import org.apache.calcite.jdbc.CalciteConnection;
  import org.apache.calcite.linq4j.tree.Expressions;
  import org.apache.calcite.linq4j.tree.ParameterExpression;
  import org.apache.calcite.schema.SchemaPlus;
  import org.apache.calcite.schema.Schemas;
  import org.apache.calcite.util.Util;
  
  import org.junit.jupiter.api.Test;
  
  import java.sql.Connection;
  import java.sql.SQLException;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Tests for a linq4j front-end and JDBC back-end.
   */
  class LinqFrontJdbcBackTest {
    @Test void testTableWhere() throws SQLException {
      final Connection connection =
          CalciteAssert.that(CalciteAssert.Config.JDBC_FOODMART).connect();
      final CalciteConnection calciteConnection =
          connection.unwrap(CalciteConnection.class);
      final SchemaPlus rootSchema = calciteConnection.getRootSchema();
      ParameterExpression c =
          Expressions.parameter(JdbcTest.Customer.class, "c");
      String s =
          Schemas.queryable(DataContexts.of(calciteConnection, rootSchema),
                  requireNonNull(rootSchema.subSchemas().get("foodmart")),
              JdbcTest.Customer.class, "customer")
              .where(
                  Expressions.lambda(
                      Expressions.lessThan(
                          Expressions.field(c, "customer_id"),
                          Expressions.constant(5)),
                      c))
              .toList()
              .toString();
      Util.discard(s);
    }
  }
  