Question

我的“国家/地区”表存在相同的错误，我发现解决方案是先删除子表，然后删除父表。现在，我添加了更多表，并尝试复制以前的操作，但是没有任何效果。我认为这是因为团队和用户具有相互引用的外键。在底部，我更改了用户表以添加引用团队的外键，但是即使我要删除那几行，也不会互相引用，执行时也会出现相同的错误。错误是针对团队，用户和ExerciseFoci表的。 ExerciseFoci是父表。

/*IF OBJECT_ID('dbo.Countries', 'U') IS NOT NULL 
DROP TABLE dbo.Countries;
IF OBJECT_ID('dbo.States', 'U') IS NOT NULL 
DROP TABLE dbo.States;
IF OBJECT_ID('dbo.Cities', 'U') IS NOT NULL 
DROP TABLE dbo.Cities;
IF OBJECT_ID('dbo.Venues', 'U') IS NOT NULL 
DROP TABLE dbo.Venues;
*/


DROP TABLE IF EXISTS Events
DROP TABLE IF EXISTS TeamMembers
DROP TABLE IF EXISTS EventAttendees
DROP TABLE IF EXISTS Teams
DROP TABLE IF EXISTS Users
DROP TABLE IF EXISTS ExerciseFoci 
DROP TABLE IF EXISTS Venues 
DROP TABLE IF EXISTS Cities
DROP TABLE IF EXISTS States
DROP TABLE IF EXISTS Countries


CREATE TABLE Countries (
countryCode varchar(5) NOT NULL,
countryName varchar(128) NOT NULL PRIMARY KEY
);

INSERT into Countries values
('US', 'United States');


CREATE TABLE States (
stateCode char(2) NOT NULL,
stateName varchar(128) NOT NULL PRIMARY KEY, 
countryName varchar(128) NOT NULL FOREIGN KEY REFERENCES 
Countries(countryName)
);

INSERT into States values 
('NJ', 'New Jersey', 'United States');


CREATE TABLE Cities (
cityName varchar(128) NOT NULL PRIMARY KEY,
stateName varchar(128) NOT NULL FOREIGN KEY REFERENCES States(stateName),
countryName varchar(128) NOT NULL FOREIGN KEY REFERENCES 
Countries(countryName)
)

INSERT into Cities values
('Newark', 'New Jersey', 'United States');


CREATE TABLE Venues (
venue varchar(128) NOT NULL PRIMARY KEY,
cityName varchar(128) NOT NULL FOREIGN KEY REFERENCES Cities(cityName),
stateName varchar(128) NOT NULL FOREIGN KEY REFERENCES States(stateName),
countryName varchar(128) NOT NULL FOREIGN KEY REFERENCES 
Countries(countryName)
)

INSERT into Venues values
('Football Field', 'Newark', 'New Jersey', 'United States');


CREATE TABLE ExerciseFoci(
name    varchar(50) PRIMARY KEY,
exercise_type   varchar(50),
primarily_outdoors bit
)

CREATE TABLE Users ( 
username    varchar(25) PRIMARY KEY,
password    varchar(25),
first_name  varchar(25),
last_name   varchar(25),
age         int,
city        varchar(128) REFERENCES Cities,
state       varchar(128) REFERENCES States,
country     varchar(128) REFERENCES Countries,
exercise_focus1 varchar(50) FOREIGN KEY references ExerciseFoci(name),
exercise_focus2 varchar(50) FOREIGN KEY references ExerciseFoci(name),
exercise_focus3 varchar(50) FOREIGN KEY references ExerciseFoci(name)
)

CREATE TABLE Teams(
name    varchar(50) PRIMARY KEY,
city        varchar(128) REFERENCES Cities,
state       varchar(128) REFERENCES States,
country     varchar(128) REFERENCES Countries,
admin1  varchar(25) FOREIGN KEY references Users(username),
admin2  varchar(25) FOREIGN KEY references Users(username),
admin3  varchar(25) FOREIGN KEY references Users(username),
exercise_focus1 varchar(50) FOREIGN KEY references ExerciseFoci(name),
exercise_focus2 varchar(50) FOREIGN KEY references ExerciseFoci(name),
exercise_focus3 varchar(50) FOREIGN KEY references ExerciseFoci(name)
)

CREATE TABLE Events(
name        varchar(50) PRIMARY KEY,
time        timestamp,
exercise_focus  varchar(50) FOREIGN KEY references ExerciseFoci,
venue       varchar(128) REFERENCES Venues,
city        varchar(128) REFERENCES Cities,
state       varchar(128) REFERENCES States,
country     varchar(128) REFERENCES Countries
)

CREATE TABLE EventAttendees(
username    varchar(25) FOREIGN KEY references Users(username),
team    varchar(50) FOREIGN KEY references Teams(name)
)

CREATE TABLE TeamMembers(
username    varchar(25) FOREIGN KEY references Users(username),
team    varchar(50) FOREIGN KEY references Teams(name)
)

ALTER TABLE Users
    ADD affiliated_team1 varchar(50) FOREIGN KEY references Teams(name);
ALTER TABLE Users
    ADD affiliated_team2 varchar(50) FOREIGN KEY references Teams(name);
ALTER TABLE Users
    ADD affiliated_team3 varchar(50) FOREIGN KEY references Teams(name);

Answer 1

您必须先删除约束，然后再删除与受约束表有关系的任何表。

您可以使用此查询获取特定表上的所有约束：

SELECT * 
FROM sys.foreign_keys
WHERE referenced_object_id = object_id('YourObj')

并使用以下查询生成放置或手动（或excel）编写放置：

SELECT 
    'ALTER TABLE [' +  OBJECT_SCHEMA_NAME(parent_object_id) +
    '].[' + OBJECT_NAME(parent_object_id) + 
    '] DROP CONSTRAINT [' + name + ']'
FROM sys.foreign_keys
WHERE referenced_object_id = object_id('YourObj')

如何解决“由于外键约束引用了对象'团队'，所以无法删除”

1 个答案: