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# frozen_string_literal: true
module ClickHouse
module MigrationSupport
class SchemaMigration
def initialize(connection, table_name: 'schema_migrations')
@connection = connection
@table_name = table_name
end
def ensure_table
return if connection.table_exists?(table_name)
query = <<~SQL
CREATE TABLE #{table_name} (
version LowCardinality(String),
active UInt8 NOT NULL DEFAULT 1,
applied_at DateTime64(6, 'UTC') NOT NULL DEFAULT now64()
)
ENGINE = ReplacingMergeTree(applied_at)
PRIMARY KEY(version)
ORDER BY (version)
SQL
connection.execute(query)
end
def all_versions
query = <<~SQL
SELECT version FROM #{table_name} FINAL
WHERE active = 1
ORDER BY (version)
SQL
connection.select(query).pluck('version')
end
def create!(**args)
insert_sql = <<~SQL
INSERT INTO #{table_name} (#{args.keys.join(',')}) VALUES (#{args.values.join(',')})
SQL
connection.execute(insert_sql)
end
private
attr_reader :connection, :table_name
end
end
end
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