Setting default values for fields using Postgres defaults¶

You can set values of certain fields automatically when not explicitly passed to a fixed value, e.g. true for a boolean field, or output of a simple SQL function, e.g. now() for a timestamp field, by setting column default values in the table definition.

Example: Say we have a field created_at in a table article which we want to be set to the current timestamp whenever a new row is added to the table:

Step 1: Modify the table¶

Edit the created_at field and set its default value as the SQL function now().

Open the console and head to Data -> article -> Modify:

To set an auto-incrementing default value

To set a default value as an auto-incrementing integer you first need to set up a sequence which will be the source of our default value.

Let’s say we have a field called roll_number which we would like to be set by default as an auto-incremented integer.

Head to Data -> SQL and run the following SQL command to create a new sequence.

CREATE SEQUENCE roll_number_seq;

Now set the default value of the roll_number field as nextval('roll_number_seq').

mutation {
  insert_article(
    objects: [
      {
        title: "GraphQL manual",
        author_id: 11
      }
    ]) {
    returning {
      id
      title
      created_at
    }
  }
}