entityMap|blocks|key|6epfv|text|表格GGroup定义列ClassRoom作为主键。这明确禁止此列中存在重复项。您的代码失败，因为您正在尝试使用ClassRoom+|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|vojl|'A/3/54'，而tabe中已存在该列中具有相同值的另一条记录。|f2bqa|可能的选项：|a4rhf|将该列的主键更改为其他值，以便更好地表示您的用例|unordered-list-item|3be6r|更改的值ClassRoom将新插入的记录中的值设置为表中尚不存在的值|dd6vi|忽略此错误:由于两条记录似乎完全重复，这可能是您在这里的最佳选择^0|2|6|B|9|1J|A|0|0|8|0|0|0|4|9|0^^$0|$]|1|@$2|3|4|5|6|7|8|R|9|@$A|S|B|T|C|D]|$A|U|B|V|C|D]|$A|W|B|X|C|D]]|E|@]|F|$]]|$2|G|4|H|6|7|8|Y|9|@$A|Z|B|10|C|D]]|E|@]|F|$]]|$2|I|4|J|6|7|8|11|9|@]|E|@]|F|$]]|$2|K|4|L|6|M|8|12|9|@]|E|@]|F|$]]|$2|N|4|O|6|M|8|13|9|@$A|14|B|15|C|D]]|E|@]|F|$]]|$2|P|4|Q|6|M|8|16|9|@]|E|@]|F|$]]]]

Table <code>GGroup</code> defines column <code>ClassRoom</code> as the primary key. This explicitly disallows duplicates in this column. Your code fails because you are trying to insert a record with <code>ClassRoom</code> <code>'A/3/54'</code>, while another record already exists in the tabe with the same value in that column.

Possible options:

<ul>
<li>change the primary key of the column to something else, that better represents your use case</li>
<li>change the value of <code>ClassRoom</code> in the newly inserted record to a value that does not yet exist in the table</li>
<li>ignore this error: since both records seem to be complete duplicates, that might be your best pick here</li>
</ul>

entityMap|blocks|key|3crr0|text|主键，必须唯一，您的教室设置为主键，不允许添加两次。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2jgdn|设置另一个变量(如递增的id)作为主键，这样您就可以更频繁地添加房间。|5qedk|问题是，为什么要两次添加相同的信息？|c5k2m|如果要将房间填充到时间表中，则不需要在GGroup中多次添加房间^0|0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|I|9|@]|A|@]|B|$]]|$2|C|4|D|6|7|8|J|9|@]|A|@]|B|$]]|$2|E|4|F|6|7|8|K|9|@]|A|@]|B|$]]|$2|G|4|H|6|7|8|L|9|@]|A|@]|B|$]]]]

Primary Keys, must be unique, your classroom is set as primary key, so you are not allowed to add it twice. 

set another variable (like an increasing id) as primary key, than you are able to add the room more often.

the question is why would you add the same information twice? 

if you want to fill in the rooms into your timetable table, you don't need to add a room more than once to the GGroup

entityMap|blocks|key|fi2j4|text|在第一个表中，您将ClassRoom字段声明为主键|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5aati|primary+key+(ClassRoom)|code-block|syntax|javascript|citv1|这意味着ClassRoom字段是行的惟一标识符，这意味着它必须是惟一的。我不确定您的数据应该在那里表示什么，但如果您的意思是在这些教室中开会的组，您可能不想使用教室作为唯一标识符，因为组可能会重用相同的教室。如何为表创建一个单独的惟一标识符，如下所示(从您的问题看，您使用的是Oracle，对吧？)|d57am|CREATE+TABLE+GGroup(
++++GGGroupId+NUMBER+GENERATED+by+default+on+null+as+IDENTITY,
++++ClassRoom+varchar(7),
++++GroupNum+number(5),
++++C_Code+varchar(6),
++++C_Name+varchar(35),+Field
++++Teacher+varchar(30)
);^0|0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|L|9|@]|A|@]|B|$]]|$2|C|4|D|6|E|8|M|9|@]|A|@]|B|$F|G]]|$2|H|4|I|6|7|8|N|9|@]|A|@]|B|$]]|$2|J|4|K|6|E|8|O|9|@]|A|@]|B|$F|G]]]]

In the first table you declared the ClassRoom field as primary key

<pre><code>primary key (ClassRoom)
</code></pre>

What that means is that the ClassRoom field is the unique identifier for the row, and that means it has to be unique. I'm not sure what your data is supposed to represent there, but if you mean that there are groups that are meeting in those class rooms, you might not want to use the class room as a unique identifier, as groups might reuse the same class room. How about creating a separate unique identifier for the table, like this (from your question looks like you are using Oracle, right?)

<pre><code> CREATE TABLE GGroup(
 GGGroupId NUMBER GENERATED by default on null as IDENTITY,
 ClassRoom varchar(7),
 GroupNum number(5),
 C_Code varchar(6),
 C_Name varchar(35), Field
 Teacher varchar(30)
);
</code></pre>

entityMap|blocks|key|541rs|text|您需要添加另一个列主键，如递增的ID，并创建一个序列来递增您的ID。例如，您可以使用触发器来完成此操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|fv53d|CREATE+TABLE+GGroup(
++++Id+NUMBER(10)++++NOT+NULL,
++++ClassRoom+varchar(7),
++++GroupNum+number(5),
++++C_Code+varchar(6),
++++C_Name+varchar(35),+Field
++++Teacher+varchar(30)
);

You+need+to+add+a+PRIMARY+KEY+constraint:

++++ALTER+TABLE+GGroup
++ADD+(
++++CONSTRAINT+GGroup_pk+PRIMARY+KEY+(Id)
++);

You+need+also+to+create+a+SEQUENCE+that+will+be+utilized+to+generate+the+unique,+auto+incremented+value.

++++CREATE+SEQUENCE+GGroup_sequence;

Finaly+you+need+a+trigger+which+is+a+stored+procedure+that+is+executed+when+the+insert+occured:

++++CREATE+OR+REPLACE+TRIGGER+GGroup_on_insert
++BEFORE+INSERT+ON+GGroup
++FOR+EACH+ROW
BEGIN
++SELECT+GGroup_sequence.nextval
++INTO+:new.Id
++FROM+dual;
END;|code-block|syntax|javascript^0|0^^$0|$]|1|@$2|3|4|5|6|7|8|H|9|@]|A|@]|B|$]]|$2|C|4|D|6|E|8|I|9|@]|A|@]|B|$F|G]]]]

You need to add an other column primary key, like an incremented ID, and create a sequence to increment your ID. you can do it with a trigger for exemple like that:

<pre><code> CREATE TABLE GGroup(
 Id NUMBER(10) NOT NULL,
 ClassRoom varchar(7),
 GroupNum number(5),
 C_Code varchar(6),
 C_Name varchar(35), Field
 Teacher varchar(30)
);

You need to add a PRIMARY KEY constraint:

 ALTER TABLE GGroup
 ADD (
 CONSTRAINT GGroup_pk PRIMARY KEY (Id)
 );

You need also to create a SEQUENCE that will be utilized to generate the unique, auto incremented value.

 CREATE SEQUENCE GGroup_sequence;

Finaly you need a trigger which is a stored procedure that is executed when the insert occured:

 CREATE OR REPLACE TRIGGER GGroup_on_insert
 BEFORE INSERT ON GGroup
 FOR EACH ROW
BEGIN
 SELECT GGroup_sequence.nextval
 INTO :new.Id
 FROM dual;
END;
</code></pre>

entityMap|blocks|key|3ab4u|text|正如其他人已经在上面的答案中指出的那样-你之所以会有这个问题，是因为你正在使用ClassRoom列作为主键在您的GGroup表脚本，即primary+key+(ClassRoom)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|6fir9|主键是什么？|at3l|一个表只能有一个主键。|unordered-list-item|6qfps|PRIMARY+KEY约束唯一标识表中的每条记录。|cc093|主键必须包含唯一值，并且不能包含空值。|70bda|这意味着您不能插入重复的值，即A/3/54在ClassRoom列。解决此错误的最简单方法之一是添加另一个列，例如GroupId通过更改或删除该表。|h8to|注意：如果GGroup表中有很多行，那么使用ALTER+table+(已经在前面的答案中说明)语句，而不是使用DROP+TABLE语句。|BOLD|8saf1|步骤1：|c8bqf|DROP+TABLE+GGroup;|code-block|syntax|javascript|7kads|步骤2：|2dgab|CREATE+TABLE+GGroup(
++++GroupId+NUMBER+GENERATED+BY+DEFAULT+ON+NULL+AS+IDENTITY,
++++ClassRoom+varchar(7),
++++GroupNum+number(5),
++++C_Code+varchar(6),
++++C_Name+varchar(35),+Field
++++Teacher+varchar(30)
);|c93i2|完成这两个步骤后，您就可以插入重复的值，而不会获得任何值ORA-00001:+unique+constraint错误。^0|1V|N|0|0|0|0|0|F|6|0|0|3|0|0|0|0|0|S|S|S|S^^$0|$]|1|@$2|3|4|5|6|7|8|17|9|@$A|18|B|19|C|D]]|E|@]|F|$]]|$2|G|4|H|6|7|8|1A|9|@]|E|@]|F|$]]|$2|I|4|J|6|K|8|1B|9|@]|E|@]|F|$]]|$2|L|4|M|6|K|8|1C|9|@]|E|@]|F|$]]|$2|N|4|O|6|K|8|1D|9|@]|E|@]|F|$]]|$2|P|4|Q|6|7|8|1E|9|@$A|1F|B|1G|C|D]]|E|@]|F|$]]|$2|R|4|S|6|7|8|1H|9|@$A|1I|B|1J|C|T]]|E|@]|F|$]]|$2|U|4|V|6|7|8|1K|9|@]|E|@]|F|$]]|$2|W|4|X|6|Y|8|1L|9|@]|E|@]|F|$Z|10]]|$2|11|4|12|6|7|8|1M|9|@]|E|@]|F|$]]|$2|13|4|14|6|Y|8|1N|9|@]|E|@]|F|$Z|10]]|$2|15|4|16|6|7|8|1O|9|@$A|1P|B|1Q|C|T]|$A|1R|B|1S|C|D]]|E|@]|F|$]]]]

As others have already pointed out in their answers above - you are having this issue because you're using ClassRoom column as the Primary Key in your GGroup table script i.e. <code>primary key (ClassRoom)</code>. 

What is PRIMARY KEY?

<ul>
<li>A table can have only ONE primary key.</li>
<li>The PRIMARY KEY constraint uniquely identifies each record in a table.</li>
<li>Primary keys must contain UNIQUE values, and cannot contain NULL values.</li>
</ul>

This means that you cannot insert a duplicate value i.e. <code>A/3/54</code> in ClassRoom column. One of the easiest ways to resolve this error will be to add another column e.g. GroupId by altering or dropping the table.

Note: If you have many rows in GGroup table then use ALTER TABLE (already shown in previous answers) statement than using DROP TABLE statement. 

Step 1: 

<pre><code>DROP TABLE GGroup;
</code></pre>

Step 2:

<pre><code>CREATE TABLE GGroup(
 GroupId NUMBER GENERATED BY DEFAULT ON NULL AS IDENTITY,
 ClassRoom varchar(7),
 GroupNum number(5),
 C_Code varchar(6),
 C_Name varchar(35), Field
 Teacher varchar(30)
);
</code></pre>

Once both the steps are followed, you can then insert duplicate values without getting any <code>ORA-00001: unique constraint</code> error.

so i have this code with simple two tables
1-GGroup
2-TimeTable 

and this is the code for them :

<pre><code>CREATE TABLE GGroup(
 ClassRoom varchar(7),
 GroupNum number(5),
 C_Code varchar(6),
 C_Name varchar(35), Field
 Teacher varchar(30),
 primary key (ClassRoom)
);

CREATE TABLE TimeTable(
 ClassRoom varchar(7),
 StudentID number(9),
 FirstName varchar(30),
 LastName varchar(30),
 primary key(ClassRoom, StudentID),
 foreign key(ClassRoom) references GGroup(ClassRoom)
);
</code></pre>

And i already inserted rows in table GGroup with np!

But now im trying to insert this row

<pre><code>insert into GGroup values (
 'A/3/54', 
 1608, 
 'ISM223', 
 'Data Warehouse &amp; Data Mining', 
 'Dr. Yasser Al-Mshhor'
);
</code></pre>

And i got this error:

<blockquote>
 ORA-00001: unique constraint (SQL_XAKKMDKZQBPBDDQFTDEXENGDH.SYS_C0025290829) violated ORA-06512: at "SYS.DBMS_SQL", line 1721
</blockquote>

I think its because this row I inserted before:

<pre><code>insert into GGroup values (
 'A/3/54', 
 1608, 
 'ISM223', 
 'Data Warehouse &amp; Data Mining', 
 'Dr. Yasser Al-Mshhor'
);
</code></pre>

How i can fix this ? I dont know alot about sql

how I can allow duplicate values in sql?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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 所以我有这个代码和两个简单的表1-GGroup 2-时间表 这是它们的代码： CREATE TABLE GGroup(    ClassRoom varchar(7),    GroupNum number(5),    C_Code varchar(6),    C_Name varchar(35), Field ...

问如何在sql中允许重复值？
EN

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问如何在sql中允许重复值？EN