Question

我正在尝试通过跟随RelBuilderExample并使用存储层为HSQLDB来学习Apache Calcite。不幸的是，当我调用Apache Calcite的builder.scan(tableName) API时，我一直收到“Table Not Found exception”。当我使用ResultSet rs = statement.executeQuery("SELECT * from file");直接查询HSQL中的数据时，我能够检索数据。以下是相关代码：

//I create an instance of RelBuilder using the Config defined below
RelBuilder builder = RelBuilder.create(config().build());
//This line throws me exception: org.apache.calcite.runtime.CalciteException: Table 'file' not found

            builder = builder.scan("file");

/**
  Building the configuration backed by HSQLDB
*/
public static Frameworks.ConfigBuilder config() throws Exception{

            //Getting the ConnectionSpec for the in memory HSQLDB
            //FileHSQLDB.URI = "jdbc:hsqldb:mem:intel"
            //FileHSQLDB.USER = "user"
            //FileHSQLDB.PASSWORD = "password"
            final ConnectionSpec cs = new ConnectionSpec(FileHSQLDB.URI, FileHSQLDB.USER, FileHSQLDB.PASSWORD, "org.hsqldb.jdbcDriver", "intel");

            //cs.url = "jdbc:hsqldb:mem:intel"
            //cs.driver = "org.hsqldb.jdbcDriver"
            //cs.username = "user"
            //cs.password = "password"
            DataSource dataSource = JdbcSchema.dataSource(cs.url, cs.driver, cs.username, cs.password);
            Connection connection = dataSource.getConnection();
            Statement statement = connection.createStatement();
            //This returns me 3 results
            ResultSet rs = statement.executeQuery("SELECT * from file");
            while(rs.next()) {
                String id = rs.getString("file_id");
                System.out.println(id);
            }
            // Next I create the rootSchema
            SchemaPlus rootSchema = Frameworks.createRootSchema(true);

            //I suspect that there is some issue in the below line. I think I 
            //am not using Apache Calcite APIs properly, but not sure what I 
            //am doing wrong.
            rootSchema.add("intel", JdbcSchema.create(rootSchema, "intel", dataSource, cs.catalog, cs.schema));
return Frameworks.newConfigBuilder().defaultSchema(rootSchema);

有人可以帮助我解决我可能做错的事情。

Answer 1

如果您的表格为file（小写），请确保在查询中引用表格名称，即"SELECT * from \"file\""。

Apache Calcite | HSQLDB - 找不到表

1 个答案: