多个外键？

本文介绍了多个外键？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我有一张桌子，应该跟踪从一个供应商运送产品到另一个供应商的日子和成本。我们（出色地说：p）将产品处理供应商（Think ... Dunder Mifflin）的运输供应商（FedEx，UPS）存储在供应商表中。所以，我的SHIPPING_DETAILS表中有三列都引用了VENDOR.no。出于某种原因，MySQL不让我将所有三个定义为外键。有什么想法吗？ $ pre $ $ $ codeREATE TABLE SHIPPING_GRID INT INT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT' ， shipping_vendor_no INT（6）NOT NULL COMMENT'对于运输供应商的VENDOR.no的外键（vendors_type必须为3）'， start_vendor_no INT（6）NOT NULL COMMENT'VENDOR的外键。 （$）b $ end_vendor_no INT（6）NOT NULL COMMENT'供应商发货给VENDOR.no的外键'， shipment_duration INT（1）DEFAULT 1 COMMENT' （5,5）NOT NULL COMMENT'美元每件货物的价格lbs（小数点后5位）'， is_flat_rate TINYINT（1）DEFAULT 0评论'1如果统一费率不考虑重量，0如果价格是由磅'， INDEX（shipping_vendor_no）， INDEX（start_vendor_no）， INDEX（end_vendor_no）， FOREIGN KEY（ （no）， FOREIGN KEY（start_vendor_no）REFERENCES VENDOR（no）， FOREIGN KEY（end_vendor_no）REFERENCES VENDOR（no））TYPE = INNODB;

编辑删除双主键定义...

是的，不幸的是，并没有解决它。现在我得到： lockquote

无法创建表 ./ 重新获得MY DB NAME /SHIPPING_GRID.frm'（errno：150）

执行phpinfo（） / b>

客户端API版本5.0.45

是的，VENDOR.no是类型int（6）。

解决方案

您定义了两次主键。试试： $ b $ pre $ $ codeREATE TABLE SHIPPING_GRID（ id INT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT'每行的唯一ID'， shipping_vendor_no INT（6）NOT NULL COMMENT'VENDOR.no的外键（shipping_type必须为3）'， start_vendor_no INT（6）NOT NULL COMMENT'VENDOR.no的外键对于从'，发货的供应商，end_vendor_no INT（6）NOT NULL COMMENT'供应商发货到'VENDOR.no的外键， shipment_duration INT（1）DEFAULT 1 COMMENT'持续时间（5,5）NOT NULL COMMENT'美元每件货物的价格lbs（小数点后5位）'， is_flat_rate TINYINT（1）DEFAULT 0评论'1，如果是统一费率不考虑重量，0如果价格是由磅'， INDEX（shipping_vendor_no）， INDEX（start_vendor_no）， INDEX（end_vendor_no），外国关键（shippi （no）， FOREIGN KEY（start_vendor_no）REFERENCES VENDOR（no）， FOREIGN KEY（end_vendor_no）REFERENCES VENDOR（no））TYPE = INNODB;

VENDOR主键必须是INT（6），而且这两个表必须是InnoDB类型。 / p>

I've got a table that is supposed to track days and costs for shipping product from one vendor to another. We (brilliantly :p) stored both the shipping vendors (FedEx, UPS) with the product handling vendors (Think... Dunder Mifflin) in a "VENDOR" table. So, I have three columns in my SHIPPING_DETAILS table that all reference VENDOR.no. For some reason MySQL isn't letting me define all three as foreign keys. Any ideas?

CREATE TABLE SHIPPING_GRID( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'Unique ID for each row', shipping_vendor_no INT(6) NOT NULL COMMENT 'Foreign key to VENDOR.no for the shipping vendor (vendors_type must be 3)', start_vendor_no INT(6) NOT NULL COMMENT 'Foreign key to VENDOR.no for the vendor being shipped from', end_vendor_no INT(6) NOT NULL COMMENT 'Foreign key to the VENDOR.no for the vendor being shipped to', shipment_duration INT(1) DEFAULT 1 COMMENT 'Duration in whole days shipment will take', price FLOAT(5,5) NOT NULL COMMENT 'Price in US dollars per shipment lbs (down to 5 decimal places)', is_flat_rate TINYINT(1) DEFAULT 0 COMMENT '1 if is flat rate regardless of weight, 0 if price is by lbs', INDEX (shipping_vendor_no), INDEX (start_vendor_no), INDEX (end_vendor_no), FOREIGN KEY (shipping_vendor_no) REFERENCES VENDOR (no), FOREIGN KEY (start_vendor_no) REFERENCES VENDOR (no), FOREIGN KEY (end_vendor_no) REFERENCES VENDOR (no) ) TYPE = INNODB;

Edited to remove double primary key definition...

Yeah, unfortunately that didn't fix it though. Now I'm getting:

Can't create table './REMOVED MY DB NAME/SHIPPING_GRID.frm' (errno: 150)

Doing a phpinfo() tells me this for mysql:

Client API version 5.0.45

Yes, the VENDOR.no is type int(6).

解决方案

You defined the primary key twice. Try:

CREATE TABLE SHIPPING_GRID( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'Unique ID for each row', shipping_vendor_no INT(6) NOT NULL COMMENT 'Foreign key to VENDOR.no for the shipping vendor (vendors_type must be 3)', start_vendor_no INT(6) NOT NULL COMMENT 'Foreign key to VENDOR.no for the vendor being shipped from', end_vendor_no INT(6) NOT NULL COMMENT 'Foreign key to the VENDOR.no for the vendor being shipped to', shipment_duration INT(1) DEFAULT 1 COMMENT 'Duration in whole days shipment will take', price FLOAT(5,5) NOT NULL COMMENT 'Price in US dollars per shipment lbs (down to 5 decimal places)', is_flat_rate TINYINT(1) DEFAULT 0 COMMENT '1 if is flat rate regardless of weight, 0 if price is by lbs', INDEX (shipping_vendor_no), INDEX (start_vendor_no), INDEX (end_vendor_no), FOREIGN KEY (shipping_vendor_no) REFERENCES VENDOR (no), FOREIGN KEY (start_vendor_no) REFERENCES VENDOR (no), FOREIGN KEY (end_vendor_no) REFERENCES VENDOR (no) ) TYPE = INNODB;

The VENDOR primary key must be INT(6), and both tables must be of type InnoDB.