使用配置单元的JDBC元数据API获得不明确的结果

我正在尝试使用

DatabaseMetaData

以类似于RDBMS的方式获取配置单元的表名

示例代码：

try (Connection con = getJdbcConnection(connectionUri, driverName, username, password);) {
        DatabaseMetaData metadata = con.getMetaData();
        ResultSet rs = metadata.getTables(null, null, tableName, null);
        while (rs.next()) {
            System.out.println(rs.getString(3));
       }

  } catch (SQLException e) {
  }

private static void registerDriver(String driverName) {
        try {
            Class.forName(driverName);
         } catch (ClassNotFoundException e) {
            LOG.error("No class found for " + driverName + ". Details: " + e);
        }
    }

private static Connection getJdbcConnection(String connectionUri, String driverName, String username,
        String password) throws SQLException{
    registerDriver(driverName);
    return DriverManager.getConnection(connectionUri, username,password);
}

    try (Connection con = getJdbcConnection(connectionUri, driverName, username, password);) {
        DatabaseMetaData metadata = con.getMetaData();
        ResultSet rs = metadata.getTables(null, schemaName, tableName, new String[] { "TABLE" });

        while (rs.next()) {
            String tName = rs.getString("TABLE_NAME");
            if (tName != null && tName.equals(tableName)) {
                LOG.info("Table [" + tableName + "] is present in the Database.");
                return true;
            }
        }
        rs.close();

        LOG.info("Table [" + tableName + "] is not present in the Database.");
        return false;

    } catch (SQLException e) {
        LOG.error("Not able to get Table Metadata . Caused By: " + e);
    }

特定数据库中没有表。使用不同的表名，我得到了不同的输出

例如：

我把表名

emp

，有3条记录的名称

emp

我放入表名

employee

，有5条记录名为

employee

我输入了表名

emp12

，它没有返回任何记录（这是预期的）

---

• 我做错什么了吗

• 我是否应该使用

  DatabaseMetaData

  检查表的存在

---

我需要在

getTables

方法中传递模式名称

签名：

ResultSet getTables(String catalog,
                  String schemaPattern,
                  String tableNamePattern,
                  String[] types)
                    throws SQLException

我通过了以下考试：

• catalog=null
• schemaPattern=配置单元架构名称
• tableNamePattern=配置单元表名
• 类型=

  新字符串[]{“表”}

示例代码：

try (Connection con = getJdbcConnection(connectionUri, driverName, username, password);) {
        DatabaseMetaData metadata = con.getMetaData();
        ResultSet rs = metadata.getTables(null, null, tableName, null);
        while (rs.next()) {
            System.out.println(rs.getString(3));
       }

  } catch (SQLException e) {
  }

private static void registerDriver(String driverName) {
        try {
            Class.forName(driverName);
         } catch (ClassNotFoundException e) {
            LOG.error("No class found for " + driverName + ". Details: " + e);
        }
    }

private static Connection getJdbcConnection(String connectionUri, String driverName, String username,
        String password) throws SQLException{
    registerDriver(driverName);
    return DriverManager.getConnection(connectionUri, username,password);
}

    try (Connection con = getJdbcConnection(connectionUri, driverName, username, password);) {
        DatabaseMetaData metadata = con.getMetaData();
        ResultSet rs = metadata.getTables(null, schemaName, tableName, new String[] { "TABLE" });

        while (rs.next()) {
            String tName = rs.getString("TABLE_NAME");
            if (tName != null && tName.equals(tableName)) {
                LOG.info("Table [" + tableName + "] is present in the Database.");
                return true;
            }
        }
        rs.close();

        LOG.info("Table [" + tableName + "] is not present in the Database.");
        return false;

    } catch (SQLException e) {
        LOG.error("Not able to get Table Metadata . Caused By: " + e);
    }

---

我需要在

getTables

方法中传递模式名

签名：

ResultSet getTables(String catalog,
                  String schemaPattern,
                  String tableNamePattern,
                  String[] types)
                    throws SQLException

我通过了以下考试：

• catalog=null
• schemaPattern=配置单元架构名称
• tableNamePattern=配置单元表名
• 类型=

  新字符串[]{“表”}

示例代码：

try (Connection con = getJdbcConnection(connectionUri, driverName, username, password);) {
        DatabaseMetaData metadata = con.getMetaData();
        ResultSet rs = metadata.getTables(null, null, tableName, null);
        while (rs.next()) {
            System.out.println(rs.getString(3));
       }

  } catch (SQLException e) {
  }

private static void registerDriver(String driverName) {
        try {
            Class.forName(driverName);
         } catch (ClassNotFoundException e) {
            LOG.error("No class found for " + driverName + ". Details: " + e);
        }
    }

private static Connection getJdbcConnection(String connectionUri, String driverName, String username,
        String password) throws SQLException{
    registerDriver(driverName);
    return DriverManager.getConnection(connectionUri, username,password);
}

    try (Connection con = getJdbcConnection(connectionUri, driverName, username, password);) {
        DatabaseMetaData metadata = con.getMetaData();
        ResultSet rs = metadata.getTables(null, schemaName, tableName, new String[] { "TABLE" });

        while (rs.next()) {
            String tName = rs.getString("TABLE_NAME");
            if (tName != null && tName.equals(tableName)) {
                LOG.info("Table [" + tableName + "] is present in the Database.");
                return true;
            }
        }
        rs.close();

        LOG.info("Table [" + tableName + "] is not present in the Database.");
        return false;

    } catch (SQLException e) {
        LOG.error("Not able to get Table Metadata . Caused By: " + e);
    }