Dropping Unique constraint from MySQL table

Question

How can I drop the  Unique Key Constraint  on a column of a MySQL table using phpMyAdmin

User · Answer

The constraint could be removed with syntax:

ALTER TABLE

As of MySQL 8.0.19, ALTER TABLE permits more general (and SQL standard) syntax for dropping and altering existing constraints of any type, where the constraint type is determined from the constraint name: ALTER TABLE tbl_name DROP CONSTRAINT symbol;

Example:

CREATE TABLE tab(id INT, CONSTRAINT unq_tab_id UNIQUE(id));

-- checking constraint name if autogenerated
SELECT * FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS WHERE TABLE_NAME = 'tab';

-- dropping constraint
ALTER TABLE tab DROP CONSTRAINT unq_tab_id;

db<>fiddle demo

User · Answer

If you want to remove unique constraints from mysql database table  use alter table with drop index    Example   create table unique constraints unid int activity name varchar 100  CONSTRAINT activty uqniue UNIQUE activity name  primary key  unid     alter table unique constraints drop index activty uqniue    Where activty uqniue is UNIQUE constraint for activity name column

User · Answer

To add UNIQUE constraint using phpmyadmin  go to the structure of that table and find below and click that     To remove the UNIQUE constraint  same way  go to the structure and scroll down till Indexes Tab and find below and click drop    Hope this works    Enjoy

User · Answer

A unique constraint is also an index    First use SHOW INDEX FROM tbl name to find out the name of the index  The name of the index is stored in the column called key name in the results of that query   Then you can use DROP INDEX   DROP INDEX index name ON tbl name   or the ALTER TABLE syntax   ALTER TABLE tbl name DROP INDEX index name

User · Answer

For WAMP 3 0   Click Structure Below Add 1 Column you will see  - Indexes  Click -Indexes and drop whichever index you want

User · Answer

my table name is buyers which has a unique constraint column emp id now iam going to drop the emp id    step 1  exec sp helpindex buyers  see the image file  step 2  copy the index address    step3  alter table buyers drop constraint  UQ  buyers  1299A860D9793F2E  alter table buyers  drop column emp id   note      Blockquote   instead of buyers change it to your table name        Blockquote   thats all column name emp id with constraints is dropped

User · Answer

while dropping unique key we use index  ALTER TABLE tbl DROP INDEX  unique address

User · Answer

You can DROP a unique constraint from a table using phpMyAdmin as requested as shown in the table below  A unique constraint has been placed on the Wingspan field  The name of the constraint is the same as the field name  in this instance

User · Answer

The indexes capable of placing a unique key constraint on a table are PRIMARY and UNIQUE indexes   To remove the unique key constraint on a column but keep the index  you could remove and recreate the index with type INDEX   Note that it is a good idea for all tables to have an index marked PRIMARY

User · Answer

First delete table go to SQL   Use this code   CREATE  TABLE service  --tablename     serviceid  int 11  NOT NULL --columns    customerid  varchar 20  DEFAULT NULL --columns    dos  varchar 30  NOT NULL --columns    productname  varchar 150  NOT NULL --columns    modelnumber  bigint 12  NOT NULL --columns    serialnumber  bigint 20  NOT NULL --columns    serviceby  varchar 20  DEFAULT NULL--columns   --INSERT VALUES INSERT INTO  service    serviceid    customerid    dos    productname    modelnumber    serialnumber    serviceby   VALUES  1   1    12 10 2018    mouse   1234555  234234324   9999     2   09    12 10 2018    vhbgj   79746385  18923984   9999     3   23    12 10 2018    mouse   123455534  11111123   9999     4   23    12 10 2018    mouse   12345  84848   9999     5   546456    12 10 2018    ughg   772882  457283   9999     6   23    12 10 2018    keyboard   7878787878  22222   1     7   23    12 10 2018    java   11  98908   9999     8   128    12 10 2018    mouse   9912280626  111111   9999     9   23    15 10 2018    hg   29829354  4564564646   9999     10   12    15 10 2018    2   5256  888888   9999    --before droping table ALTER TABLE  service    ADD PRIMARY KEY   serviceid      ADD  unique modelnumber    modelnumber      ADD  unique serialnumber    serialnumber      ADD unique modelnumber 2    modelnumber    --after droping table ALTER TABLE  service    ADD PRIMARY KEY   serviceid      ADD  modelnumber    modelnumber      ADD  serialnumber    serialnumber      ADD modelnumber 2    modelnumber

[mysql] Dropping Unique constraint from MySQL table

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