我正在尝试通过遵循RelBuilderExample来学习Apache Calcite，存储层是HSQLDB。 不幸的是，当我调用Apache Calcite的API时builder.scan(tableName)我不断收到"找不到表异常"。当我直接使用ResultSet rs = statement.executeQuery("SELECT * from file");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);
有人可以帮助我做错什么吗？
如果您的表是file(小写(，请确保在查询中引用表名，即"SELECT * from "file"".