Adicione a chave primária à tabela existente SQL
alter table Persion add primary key (persionId,Pname,PMID)
Agreeable Antelope
alter table Persion add primary key (persionId,Pname,PMID)
ALTER TABLE `tblauto`
ADD PRIMARY KEY (`id`);
--CREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
PRIMARY KEY (ID)
);