Question

这是我第一次做MySQL。我正在使用MySQL 5.6命令行客户端，我试图显示表，它显示空集。这是我想要执行的脚本语句：

CREATE DATABASE ACMEOnline;

CREATE TABLE ITEM(Item_Number Integer DEFAULT 0, Item_Name Varchar(35) DEFAULT 'No Data', Model_Num Varchar(15) DEFAULT 'No Data',
 ->Description Varchar(255) DEFAULT 'No Data', Price DOUBLE(8,2) NOT NULL DEFAULT 0.00, Category_Name Varchar(35), 
 ->CONSTRAINT item_item_number_pk PRIMARY KEY(Item_Number), 
 ->CONSTRAINT item_category_name_fk FOREIGN KEY(Category_Name) REFERENCES CATEGORY(Category_Name));

CREATE TABLE CATEGORY(Category_Name Varchar(35), ShippingPerPound DOUBLE(4,2), DiscountsAllowed Char(1), 
 ->CONSTRAINT category_category_name_pk PRIMARY KEY(Category_Name));

CREATE TABLE LINE_ITEM(Quantity TINYINT(2), Shipping_Amount DOUBLE(6,2), OrderID Integer, Item_Number Integer,
 ->CONSTRAINT line_item_orderid_fk FOREIGN KEY(OrderID) REFERENCES ORDER_ITEM(OrderID),
 ->CONSTRAINT line_item_item_number_fk FOREIGN KEY(Item_Number) REFERENCES ORDER_ITEM(Item_Number));

CREATE TABLE ORDER_ITEM(OrderID Integer, Item_Number Integer, PRIMARY KEY(OrderID, Item_Number));

CREATE TABLE ORDER(OrderID Integer, Total DOUBLE(10,2), CONSTRAINT order_orderid_pk PRIMARY KEY(OrderID), CustomerID Integer, OfferCode Varchar(15),
  ->CONSTRAINT customer_offer_customerid_fk FOREIGN KEY(CustomerID) REFERENCES CUSTOMER(CustomerID),
  ->CONSTRAINT customer_offer_offercode_fk FOREIGN KEY(OfferCode) REFERENCES OFFER(OfferCode));

 CREATE TABLE CUSTOMER_OFFER(CustomerID Integer, OfferCode Varchar(15), PRIMARY KEY(CustomerID, OfferCode));

 CREATE TABLE OFFER(OfferCode Varchar(15), MinAmount DOUBLE(4,2) NOT NULL, Discount Varchar(35), ExpirationDate Char(8) NOT NULL, 
  ->CONSTRAINT offer_offercode_pk PRIMARY KEY(OfferCode));

 CREATE TABLE CUSTOMER(CustomerID Integer, CustomerName Varchar(50), Address Varchar(150), Email Varchar(80), 
  ->CONSTRAINT customer_customerid_pk PRIMARY KEY(CustomerID));

 CREATE TABLE BUSINESS(PurchaseTerms Varchar(50), CustomerID Integer, CONSTRAINT business_customerid_pk PRIMARY KEY(CustomerID),
  ->FOREIGN KEY(CustomerID) REFERENCES CUSTOMER(CustomerID));

 CREATE TABLE HOME(CreditCardNum BIGINT(16) NOT NULL, CardExpiration Char(7) NOT NULL, CONSTRAINT home_customerid_pk PRIMARY KEY(CustomerID),
  ->FOREIGN KEY(CustomerID) REFERENCES CUSTOMER(CustomerID));

 CREATE TABLE CONTACT(ContactName Varchar(50), ContactPhone Char(12) NOT NULL, CONSTRAINT contact_contactname_pk PRIMARY KEY(ContactName),
  ->FOREIGN KEY(Customer ID) REFERENCES BUSINESS(CustomerID));

 SHOW TABLES;
 DESCRIBE ITEM;
 DESCRIBE CATEGORY;
 DESCRIBE LINE_ITEM;
 DESCRIBLE ORDER_ITEM;
 DESCRIBE ORDER;
 DESCRIBE CUSTOMER_OFFER;
 DESCRIBE OFFER;
 DESCRIBE CUSTOMER;
 DESCRIBE BUSINESS;
 DESCRIBE HOME;
 DESCRIBE CONTACT;

在MySQL 5.6命令行客户端中：

 mysql> use acmeonline;
 Database changed
 mysql> show tables;
 Empty set (0.00 sec)
 mysql> describe item; //the rest of the table names repeated.
 ERROR 1146 (42S02): Table 'acmeonline.item' doesn't exist

我不知道最后一行是什么意思，即使我在一个名为acmeonline的数据库中创建了一个项目表。也许我错过了一些重要的东西，但我不知道是什么。非常感谢您的帮助！

Answer 1

不要再使用show tables命令了。了解如何使用information_schema观看次数。我怀疑你在错误的数据库中创建了表。

执行以下命令

SELECT * FROM information_schema.tables

在那里寻找你的桌子。 information_schema视图对于任何开发人员/ dba都是必不可少的。

Answer 2

您应该在创建数据库后更改数据库。现在，所有表都驻留在连接到mysql的最后一个数据库中，或者在执行CREATE TABLE语句之前手动更改的最后一个数据库。

mysql> CREATE DATABASE ACMEOnline;
Query OK, 1 row affected (0.00 sec)

mysql> USE ACMEOnline;
Database changed

然后创建所有表格

mysql> CREATE TABLE test(id int);
Query OK, 0 rows affected (0.02 sec)

mysql> SHOW TABLES;
+----------------------+
| Tables_in_acmeonline |
+----------------------+
| test                 |
+----------------------+
1 row in set (0.00 sec)

确保在正确的数据库中创建表的另一种方法是使用点表示法<database_name>.<table_name>

mysql> USE mysql;
Database changed

mysql> CREATE TABLE ACMEOnline.test1(id int);
Query OK, 0 rows affected (0.01 sec)

mysql> USE ACMEOnline;
Database changed

mysql> SHOW TABLES;
+----------------------+
| Tables_in_acmeonline |
+----------------------+
| test                 |
| test1                |
+----------------------+
2 rows in set (0.00 sec)

如何在MySQL中显示表格？继续显示空集

2 个答案: