java枚举和postgresql枚举 [英] java enum and postgresql enum

问题描述

CREATE TABLE customers
(
  first_name character varying(15),
  second_name character varying(20),
  login character varying(15) NOT NULL,
  password character varying(15),
  email character varying(40),
  gender gender,
  register_date date,
  date_of_birth date,
  address character varying(40),
  address_number integer,
  town character varying(20),
  CONSTRAINT login PRIMARY KEY (login)
)

我有此表，并创建了一个性别枚举，例如：

I have this table and I created an enum of gender such as:

CREATE TYPE gender AS ENUM ( 'F', 'M',);

我正在尝试使用PreparedStatement
从eclipse java插入客户数据，但是有一个错误，例如ERROR：性别列的性别类型，但表达式的字符类型不同
提示：您将需要重写或强制转换表达式。

I am trying to insert into customers data from eclipse java with PreparedStatement but there is an error such as ERROR: column "gender" is of type gender but expression is of type character varying Hint: You will need to rewrite or cast the expression.

我的Java代码如下：

My Java code looks like:

PreparedStatement pre_state;

public enum gendertype {
    F,
    M;
}

pre_state = conn.prepareStatement("INSERT INTO"
            + " customers VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");
pre_state.set(6, gendertype.F.toString());

推荐答案

我对这个答案一无所知

PostgreSQL给出了答案

PostgreSQL provides the answer when it says

提示：您将需要重写或强制转换表达式

Hint: You will need to rewrite or cast the expression

Java代码正在创建一个字符串文字值，表示Java枚举类型类型。

The Java code is creating a string literal value that represents the Java enum gendertype type.

通过在值 :: gender 。

因此有效输入应为

'F'::gender

或

'M'::gender

这是因为所有PostgreSQL类型具有一个输入方法，该输入方法采用文本表示形式并将其转换为内部形式。

This works because all PostgreSQL types have a input method that takes a text representation and converts that to the internal form.

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