How to allow duplicate entry in mysql

1. Does MySQL allow duplicate entries?
2. How do I allow duplicates in primary key?
3. How do I INSERT duplicate records in SQL?
4. What is duplicate entry for key MySQL update?
5. How do I allow duplicates in set?
6. Which key can accept duplicate values?
7. Does Set allow duplicate keys?
8. What causes duplicate entries?
9. What does duplicate entry mean in MySQL?
10. How many entries can MySQL handle?
11. Does SQL count duplicates?
12. Does a set allow duplicate entries?
13. How can I pass duplicate entries?
14. How can insert 1000 records at a time in MySQL?
15. Can MySQL handle 1 million records?
16. How to remove select limit in MySQL?

Does MySQL allow duplicate entries?

Generally, tables or result sets sometimes contain duplicate records. Most of the times it is allowed but sometimes it is required to stop duplicate records. It is required to identify duplicate records and remove them from the table.

How do I allow duplicates in primary key?

You can't have duplicate values in the primary key or else it wouldn't be a primary key.

How do I INSERT duplicate records in SQL?

INSERT INTO table_name(c1) VALUES(c1) ON DUPLICATE KEY UPDATE c1 = VALUES(c1) + 1; The statement above sets the value of the c1 to its current value specified by the expression VALUES(c1) plus 1 if there is a duplicate in UNIQUE index or PRIMARY KEY .

What is duplicate entry for key MySQL update?

ON DUPLICATE KEY UPDATE is a MariaDB/MySQL extension to the INSERT statement that, if it finds a duplicate unique or primary key, will instead perform an UPDATE. The row/s affected value is reported as 1 if a row is inserted, and 2 if a row is updated, unless the API's CLIENT_FOUND_ROWS flag is set.

How do I allow duplicates in set?

Set is not allowed to store duplicated values by definition. If you need duplicated values, use a List. As specified on the documentation of the interface, when you try to add a duplicated value, the method add returns false, not an Exception. Save this answer.

Which key can accept duplicate values?

A primary key is a series of unique values. So you can keep your duplicate data or you can have a primary key, but not both. Alternatively you can use a surrogate key, by adding an ID column to the table and populating it from a sequence.

Does Set allow duplicate keys?

The main thing is, objects that are stored in HashSet must override equals() for check for equality, and hashCode() methods for no duplicate value are stored in our set. HashMap is an implementation of Map Interface, which maps a key to value. Duplicate keys are not allowed in a Map.

What causes duplicate entries?

Data aggregation and human typing errors are some of the sources of duplicate data. Customers may also provide a company with different information at different points in time. Hence, businesses should consider removing duplicate records from their Database.

What does duplicate entry mean in MySQL?

When creating a primary key or unique constraint after loading the data, you can get a “Duplicate entry for key 'PRIMARY'” error. If the data in the source database is valid and there are no any duplicates you should check which collation is used in your MySQL database.

How many entries can MySQL handle?

Row Size Limit Examples

The MySQL maximum row size limit of 65,535 bytes is demonstrated in the following InnoDB and MyISAM examples. The limit is enforced regardless of storage engine, even though the storage engine may be capable of supporting larger rows.

Does SQL count duplicates?

Using the GROUP BY and HAVING clauses we can show the duplicates in table data. The GROUP BY statement in SQL is used to arrange identical data into groups with the help of some functions. i.e if a particular column has the same values in different rows then it will arrange these rows in a group.

Does a set allow duplicate entries?

A Set is a Collection that cannot contain duplicate elements. It models the mathematical set abstraction.

How can I pass duplicate entries?

In order to duplicate the entry in Tally, place the cursor on the entry you wish to duplicate. Press ALT+2. Or, you can also go by clicking the DUPLICATE button available below the daybook screen. If the user needs any changes in date, narration, or amount, additionally Press Ctrl+ A or just press Enter to accept.

How can insert 1000 records at a time in MySQL?

insert into table my_table(col1, col2) VALUES (val1_1, val2_1), (val1_2, val2_2); Save this answer. Show activity on this post. It's okay to insert 1000 rows.

Can MySQL handle 1 million records?

Save this answer. Show activity on this post. Millions of rows is fine, tens of millions of rows is fine - provided you've got an even remotely decent server, i.e. a few Gbs of RAM, plenty disk space. You will need to learn about indexes for fast retrieval, but in terms of MySQL being able to handle it, no problem.

How to remove select limit in MySQL?

You can toggle the LIMIT clause added by MySQL Workbench via the SQL Editor tab within the application preferences (Edit menu -> Preferences...). Simply un-check the "Limit Rows" option within the Query Results section as pictured below.