B4J Question Unique Primary Key

[Pelky]

Is there a way to ensure that a column (field) is unique in an sql database?

I have looked at INTEGER PRIMARY KEY but I am looking to ensure a STRING within the Database is unique; ie a name + date of birth

Thank you in advance

 

[DarkoT]

Hi,
which db you are using? SqlLite, MySql or something else? There is only way to check with table description if some field already exists or not... I guess you have xxx tables in database and want to have unique field in one of this tables? Or?

 

[Num3]

You can create the table with a field with auto_increment + primary key.
The database will increase the field by 1 each time you create a record, you don't need to do anything

   CREATE TABLE YOURTABLE
   (
      id INT AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(90),
      birthday VARCHAR(16)
   )

If you want to ensure two fields are unique try this:

   CREATE TABLE YOURTABLE
   (
      id INT AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(90),
      birthday VARCHAR(16),
      CONSTRAINT UC_Person UNIQUE (name,birthday)
   )

But be aware, if your try to insert a record that collides there will be errors.

Take a look here W3schools

 

[Erel]

You can use the UNIQUE constraint when you create the table:

col1 TEXT UNIQUE