Question

我有2张桌子顾客＆amp;我的Oracle数据库中的帐户。我有序列号用于为两个表生成代理键值。

CREATE SEQUENCE         customers_seq   NOCACHE;
CREATE SEQUENCE         accounts_seq    NOCACHE;


CREATE TABLE            customers
(
customer_surrogate_id   NUMBER(10),     
customer_id             VARCHAR2(8) UNIQUE      NOT NULL,
customer_password       VARCHAR2(20),
customer_name           VARCHAR2(20), 
customer_pan            VARCHAR2(10)    UNIQUE,
customer_email_id       VARCHAR2(20)    UNIQUE,
CONSTRAINT              customer_pk 
    PRIMARY KEY (customer_surrogate_id)
);

CREATE TABLE            accounts
(
accounts_surrogate_id   NUMBER(10),
account_id              VARCHAR2(10)    UNIQUE      NOT NULL,
customer_surrogate_id   NUMBER(10),
account_type            VARCHAR2(10),
account_currency        VARCHAR2(20),
account_balance         NUMBER(20, 2), 
CONSTRAINT              accounts_pk 
    PRIMARY KEY (accounts_surrogate_id), 
CONSTRAINT          accounts_fk
    FOREIGN KEY (customer_surrogate_id) 
        REFERENCES  customers(customer_surrogate_id)
);

我知道如何使用sequence_name.NEXTVAL＆amp;插入语句中的sequence_name.CURRVAL来执行引用

问题在于使用NEXTVAL＆amp; CURRVAL是假设两个表的插入顺序发生，如

insert into Customers(// use NEXTVAL here)
insert into Accounts(// use CURRVAL here to reference the above row in Customers)

但是在我的java应用程序中，Customers表的多个插入可以在Accounts表中发生一次插入之前发生。 CURRVAL将返回Customers表的最后一个插入行的值。

在Accounts表中插入行时，我可以在我的应用程序中获取customers_id值。是否应使用customer_id查询Customers表以获取customer_surrogate_id，如下所示？

insert into Customers(// use NEXTVAL here)
...
insert into Accounts(// use the customer_id to query and find customer_surrogate_id)

在这种情况下，有没有更好的方法来引用Customers表？

编辑：我正在使用JDBC访问数据库。

Answer 1

只需选择值，并将其存储在变量中：

long customer1Id = selectNextValueFromSequence("customers_seq");
long customer2Id = selectNextValueFromSequence("customers_seq");

insertCustomerWithId(customer1Id);
insertCustomerWithId(customer2Id);

insertAccountWithCustomerId(customer1Id);
insertAccountWithCustomerId(customer2Id);

引用代理键

1 个答案: