Question

从Java开始，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管理员中，它回来了，但不知道如何从我准备好的声明中获取它：

        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

我没有足够的声誉来评论和我的编辑遭到拒绝，很抱歉重新发布hd1已经接受的答案。

executeUpdate期望不返回;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 2

调用executeUpdate()期望语句没有结果。调用stmt.execute（）然后调用stmt.getResultSet（）

Answer 3

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);

如果您还有其他问题，请发表评论。

Answer 4

JDBC内置支持返回插入语句的主键值。从您的SQL中删除“ returning”子句，并指定PreparedStatement.RETURN_GENERATED_KEYS作为prepareStatment（...）调用的第二个参数。然后，可以在调用executeUpdate（）之后，通过对PreparedStatement对象调用stmt.getGeneratedKeys（）来获取生成的主键。

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

PreparedStatement stmt = connection.prepareStatement(insertStatement,
    PreparedStatement.RETURN_GENERATED_KEYS);

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 resultSet = stmt.getGeneratedKeys();
resultSet.next();
int lastInsertedPersonID = resultSet.getInt(1);

通过Java从Postgresql获取RETURNING值

4 个答案: