通过Java从Postgresql获取RETURNING值

Question

从Java，我在Postgresql中调用一个带有插入的预准备语句，该插件具有我的标识列的RETURNING子句。在PG管理员它回来了，但不知道如何从我准备好的声明中得到它：

        String insertStatement = "INSERT INTO person(\n" +
                "            name, address, phone, customer_type, \n" +
                "            start_dtm)\n" +
                "    VALUES (?, ?, ?, ?, \n" +
                "            ?)\n" +
                "    RETURNING person_id;";


        PreparedStatement stmt = connection.prepareStatement(insertStatement);

        stmt.setObject(1, perToSave.getName(null));
        stmt.setObject(2, editToSave.getAddress());
        stmt.setObject(3, editToSave.getPhone());
        stmt.setObject(4, editToSave.getCustType());
        long epochTime = java.lang.System.currentTimeMillis();
        stmt.setObject(5, new java.sql.Date(epochTime));

        stmt.executeUpdate();

Answer 1

根据javadoc，PreparedStatement继承自Statement，后者包含getResultSet（）方法。换句话说，试试这个：

String insertStatement = "INSERT INTO person(\n" +
                "            name, address, phone, customer_type, \n" +
                "            start_dtm)\n" +
                "    VALUES (?, ?, ?, ?, \n" +
                "            ?)\n" +
                "    RETURNING person_id;";


PreparedStatement stmt = connection.prepareStatement(insertStatement);

stmt.setObject(1, perToSave.getName(null));
stmt.setObject(2, editToSave.getAddress());
stmt.setObject(3, editToSave.getPhone());
stmt.setObject(4, editToSave.getCustType());
long epochTime = java.lang.System.currentTimeMillis();
stmt.setObject(5, new java.sql.Date(epochTime));

stmt.executeUpdate();
ResultSet last_updated_person = stmt.getResultSet();
last_updated_person.next();
int last_updated_person_id = last_updated_person.getInt(1);

如果您有其他问题，请发表评论。

Answer 2

我没有足够的声誉评论和我的编辑被拒绝，所以很抱歉重新张贴hd1已经接受的答案。

executeUpdate期望没有返回;使用执行。在尝试检索值之前检查是否有一些结果。

String insertStatement = "INSERT INTO person(\n" +
                "            name, address, phone, customer_type, \n" +
                "            start_dtm)\n" +
                "    VALUES (?, ?, ?, ?, \n" +
                "            ?)\n" +
                "    RETURNING person_id;";

PreparedStatement stmt = connection.prepareStatement(insertStatement);

stmt.setObject(1, perToSave.getName(null));
stmt.setObject(2, editToSave.getAddress());
stmt.setObject(3, editToSave.getPhone());
stmt.setObject(4, editToSave.getCustType());
long epochTime = java.lang.System.currentTimeMillis();
stmt.setObject(5, new java.sql.Date(epochTime));

stmt.execute();
ResultSet last_updated_person = stmt.getResultSet();
if(last_updated_person.next()) {
   int last_updated_person_id = last_updated_person.getInt(1);
}

Answer 3

调用executeUpdate()预计声明没有结果。调用stmt.execute（）然后调用stmt.getResultSet（）