我如何解决外键没有索引父项?
How can i solve foreign key no index parent?
我在过去 2 天才开始学习 SQL,现在我遇到了使用外键约束在不同 table 上链接列的问题。
下面是我的代码。
CREATE TABLE analytics (
id INT NOT NULL,
status BOOLEAN,
server_id INT, /* link with server info*/
source_id INT, /*link with input source*/
ext VARCHAR(5),
startframe_id_x INT,
endframe_id_x INT,
mask VARCHAR(20),
label VARCHAR(20),
countline INT,
det_deviceid INT,
processing_period TIME,
PRIMARY KEY(id),
FOREIGN KEY (server_id) REFERENCES server_info(id),
FOREIGN KEY (source_id) REFERENCES input_source(id)
);
CREATE TABLE statistics (
id INT NOT NULL,
source_id INT, /*link with input source*/
analytic_id INT, /*link with analytic*/
time_recorded TIMESTAMP,
duration TIME, /*link with analytics processing period*/
counter INT,
PRIMARY KEY (id),
FOREIGN KEY (source_id) REFERENCES input_source(id),
FOREIGN KEY (analytic_id) REFERENCES analytics(id),
FOREIGN KEY (duration) REFERENCES analytics(processing_period)
);
问题出现在这一行
FOREIGN KEY (duration) REFERENCES analytics(processing_period)
我不确定并用了无数小时搜索和找出解决方案但仍然无法修复它。
它给出了这样的错误"ER_FK_INDEX_PARENT: Failed to add the foreign key constraint. Missing index for constraint 'statistics_ibfk_3' in the referenced table 'analytics'"
谁能说出为什么会出现这个问题?我正在使用 Popsql 编辑我的代码并使用 mysql 数据库。
希望得到一些解释或解决方案。
你的第二个 table 应该是这样的:
CREATE TABLE statistics (
id INT NOT NULL,
source_id INT, /*link with input source*/
analytic_id INT, /*link with analytic*/
time_recorded TIMESTAMP,
counter INT,
PRIMARY KEY (id),
FOREIGN KEY (source_id) REFERENCES input_source(id),
FOREIGN KEY (analytic_id) REFERENCES analytics(id)
);
请注意,duration
已被删除。如果要处理周期,那么用JOIN
匹配到analytics
table.
我在过去 2 天才开始学习 SQL,现在我遇到了使用外键约束在不同 table 上链接列的问题。 下面是我的代码。
CREATE TABLE analytics (
id INT NOT NULL,
status BOOLEAN,
server_id INT, /* link with server info*/
source_id INT, /*link with input source*/
ext VARCHAR(5),
startframe_id_x INT,
endframe_id_x INT,
mask VARCHAR(20),
label VARCHAR(20),
countline INT,
det_deviceid INT,
processing_period TIME,
PRIMARY KEY(id),
FOREIGN KEY (server_id) REFERENCES server_info(id),
FOREIGN KEY (source_id) REFERENCES input_source(id)
);
CREATE TABLE statistics (
id INT NOT NULL,
source_id INT, /*link with input source*/
analytic_id INT, /*link with analytic*/
time_recorded TIMESTAMP,
duration TIME, /*link with analytics processing period*/
counter INT,
PRIMARY KEY (id),
FOREIGN KEY (source_id) REFERENCES input_source(id),
FOREIGN KEY (analytic_id) REFERENCES analytics(id),
FOREIGN KEY (duration) REFERENCES analytics(processing_period)
);
问题出现在这一行
FOREIGN KEY (duration) REFERENCES analytics(processing_period)
我不确定并用了无数小时搜索和找出解决方案但仍然无法修复它。
它给出了这样的错误"ER_FK_INDEX_PARENT: Failed to add the foreign key constraint. Missing index for constraint 'statistics_ibfk_3' in the referenced table 'analytics'"
谁能说出为什么会出现这个问题?我正在使用 Popsql 编辑我的代码并使用 mysql 数据库。
希望得到一些解释或解决方案。
你的第二个 table 应该是这样的:
CREATE TABLE statistics (
id INT NOT NULL,
source_id INT, /*link with input source*/
analytic_id INT, /*link with analytic*/
time_recorded TIMESTAMP,
counter INT,
PRIMARY KEY (id),
FOREIGN KEY (source_id) REFERENCES input_source(id),
FOREIGN KEY (analytic_id) REFERENCES analytics(id)
);
请注意,duration
已被删除。如果要处理周期,那么用JOIN
匹配到analytics
table.