创建表时出错

Question

这是我的声明，我在Customer_T上发生错误。的错误状态：在使用本

"01:22:05 DROP TABLE customer_t Error Code: 1051. Unknown table 'energyefficient.customer_t' 0.016 sec" 

CREATE TABLE Customer_t 
      (CustomerID INT    NOT NULL, 
       Name   VARCHAR(45)  NOT NULL, 
       Address  VARCHAR(256)    , 
       Email  VARCHAR(100)    ,  
       Phone  VARCHAR(16)    , 
CONSTRAINT PK_CustomerID PRIMARY KEY (CustomerID)); 


CREATE TABLE Order_t 
      (OrderID   INT  NOT NULL, 
       OrderDate   DATE   NULL, 
       CustomerID   INT  NOT NULL, 
CONSTRAINT PK_OrderID PRIMARY KEY (OrderID), 
CONSTRAINT FK_CustomerID FOREIGN KEY (CustomerID) REFERENCES customer_t(CustomerID)); 

CREATE TABLE Equipment 
      (EquipmentID   INT  NOT NULL, 
       EquipmentType  VARBINARY(12)  , 
       YearOfManufacture INT    , 
       Cost    DECIMAL(9,2)  , 
      Maker    VARCHAR(45)  , 
      Model    VARCHAR(45)  , 
      CustomerID   INT    , 
CONSTRAINT EquipmentID_PK PRIMARY KEY (EquipmentID), 
CONSTRAINT CustomerID_FK FOREIGN KEY (CustomerID) REFERENCES Customer_t(CustomerID)); 

CREATE TABLE Order_Line_t 
       (OrderLineID  INT  NOT NULL, 
       OrderID    INT  NOT NULL, 
       EquipmentID   INT  NOT NULL, 
       OrderLineCost  DECIMAL(9,2)  , 
CONSTRAINT OrderLineID_PK PRIMARY KEY (OrderLineID), 
CONSTRAINT OrderID_FK1 FOREIGN KEY (OrderID) REFERENCES Order_t(OrderID), 
CONSTRAINT EquipmentID_FK2 FOREIGN KEY (EquipmentID) REFERENCES Equipment_t(EquipmentID)); 

CREATE TABLE MaintenanceSchedule_t 
      (MaintenanceID  INT   NOT NULL, 
       MaintenanceType  VARCHAR(45) NOT NULL, 
       Schedule_Date   DATE  NOT NULL, 
       EquipmentID   INT   NOT NULL, 
       ServiceID   INT     , 
CONSTRAINT MaintenanceID_PK PRIMARY KEY (MaintenanceID), 
CONSTRAINT EquipmentID_FK3 FOREIGN KEY (EquipmentID) REFERENCES Equipment(EquipmentID)); 

CREATE TABLE Service 
      (ServiceID   INT   NOT NULL, 
       EstimatedCost  DECIMAL(9,2) NOT NULL, 
       Status    VARCHAR(16) NOT NULL, 
       ServiceDate   DATE     , 
       EquipmentID   INT   NOT NULL, 
       EmployeeID   INT   NOT NULL, 
       ActualCost   DECIMAL(9,2)   , 
       ServiceType   VARCHAR(45) NOT NULL, 
       Notes    VARCHAR(2000)  , 

CONSTRAINT ServiceID_PK PRIMARY KEY (ServiceID), 
CONSTRAINT EquipmentID_FK FOREIGN KEY (EquipmentID) REFERENCES Equipment(EquipmentID)); 

CREATE TABLE Employee_t 
      (EmployeeID   INT   NOT NULL, 
       AnnualSalary  DECIMAL(9,2)   , 
       Name    VARCHAR(45) NOT NULL, 
       DOB     DATE     , 
       POSITION   VARCHAR(45)   , 
CONSTRAINT EmployeeID_PK PRIMARY KEY (EmployeeID)); 

Answer 1

尝试：

组FOREIGN_KEY_CHECKS = 0; drop table energyefficient.customer_t; set foreign_key_checks = 1;

有些时候需要将外键检查设置为0;

感谢

Answer 2

可能性1：

你的表创建脚本没有任何错误。

按所示的错误消息：

"01:22:05 DROP TABLE customer_t 
Error Code: 1051. Unknown table 'energyefficient.customer_t' 0.016 sec" 

您正在试图删除该表customer_t在一个名为energyefficient数据库。

可能的原因是您已经在其他数据库中创建了表并试图从别处删除该表。

可能性2：

您可以修改drop table包括if exists条款，使被抑制的错误而忽视默默但有警告，如果这样的表不存在。

例：

DROP TABLE IF EXISTS customer_t; 

在情况下，如果你是表第一丢弃父，全局变量foreign_key_checks更改为false和运行滴。

set foreign_key_checks = 0; 
DROP TABLE IF EXISTS customer_t; 
-- other drop statements here. 
set foreign_key_checks = 1; -- reset to default