migrations database table code example
Example 1: how database migration work
<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">
<changeSet id="1" author="bob">
<createTable tableName="department">
<column name="id" type="int">
<constraints primaryKey="true" nullable="false"/>
</column>
<column name="name" type="varchar(50)">
<constraints nullable="false"/>
</column>
<column name="active" type="boolean" defaultValueBoolean="true"/>
</createTable>
</changeSet>
</databaseChangeLog>
Example 2: how database migration work
class ChangeProductsPrice < ActiveRecord::Migration[5.0]
def change
reversible do |dir|
change_table :products do |t|
dir.up { t.change :price, :string }
dir.down { t.change :price, :integer }
end
end
end
end