Modifying the database schema

sqlc parses CREATE TABLE and ALTER TABLE statements in order to generate the necessary code.

CREATE TABLE authors (
  id          SERIAL PRIMARY KEY,
  birth_year  int    NOT NULL
);

ALTER TABLE authors ADD COLUMN bio text NOT NULL;
ALTER TABLE authors DROP COLUMN birth_year;
ALTER TABLE authors RENAME TO writers;

package db

type Writer struct {
	ID  int
	Bio string
}

Handling SQL migrations

sqlc does not perform database migrations for you. However, sqlc is able to differentiate between up and down migrations. sqlc ignores down migrations when parsing SQL files.

sqlc supports parsing migrations from the following tools:

goose

-- +goose Up
CREATE TABLE post (
    id    int NOT NULL,
    title text,
    body  text,
    PRIMARY KEY(id)
);

-- +goose Down
DROP TABLE post;

package db

type Post struct {
	ID    int
	Title sql.NullString
	Body  sql.NullString
}

sql-migrate

-- +migrate Up
-- SQL in section 'Up' is executed when this migration is applied
CREATE TABLE people (id int);


-- +migrate Down
-- SQL section 'Down' is executed when this migration is rolled back
DROP TABLE people;

package db

type People struct {
	ID int32
}

tern

CREATE TABLE comment (id int NOT NULL, text text NOT NULL);
---- create above / drop below ----
DROP TABLE comment;

package db

type Comment struct {
	ID   int32
	Text string
}

golang-migrate

Warning: golang-migrate interprets migration filenames numerically. However, sqlc parses migration files in lexicographic order. If you choose to have sqlc enumerate your migration files, make sure their numeric ordering matches their lexicographic ordering to avoid unexpected behavior. This can be done by prepending enough zeroes to the migration filenames.

This doesn’t work as intended.

1_initial.up.sql
...
9_foo.up.sql
# this migration file will be parsed BEFORE 9_foo
10_bar.up.sql

This worked as intended.

001_initial.up.sql
...
009_foo.up.sql
010_bar.up.sql

In 20060102.up.sql:

CREATE TABLE post (
    id    int NOT NULL,
    title text,
    body  text,
    PRIMARY KEY(id)
);

In 20060102.down.sql:

DROP TABLE post;

package db

type Post struct {
	ID    int
	Title sql.NullString
	Body  sql.NullString
}

dbmate

-- migrate:up
CREATE TABLE foo (bar INT NOT NULL);

-- migrate:down
DROP TABLE foo;

package db

type Foo struct {
	Bar int32
}