Module: DynamicMigrations::Postgres::Server::Database::ValidationsLoader

Included in:
DynamicMigrations::Postgres::Server::Database
Defined in:
lib/dynamic_migrations/postgres/server/database/validations_loader.rb

Instance Method Summary collapse

Instance Method Details

#create_database_validations_cache ⇒ Object 



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# File 'lib/dynamic_migrations/postgres/server/database/validations_loader.rb', line 8

def create_database_validations_cache
  connection.exec(<<~SQL)
    CREATE MATERIALIZED VIEW #{Postgres.cache_schema_name}.dynamic_migrations_validations_cache AS
      SELECT
        nspname AS schema_name,
        pg_constraint_class.relname AS table_name,
        array_agg(columns.column_name ORDER BY columns.column_name) AS columns,
        pg_get_constraintdef(pg_constraint.oid) AS check_clause,
        conname AS validation_name,
        obj_description(pg_constraint.oid, 'pg_constraint') AS description,
        -- in case we need to update this query in a later version of DynamicMigrations
        1 as table_version
      FROM pg_catalog.pg_constraint
      INNER JOIN pg_catalog.pg_class pg_constraint_class
        ON pg_constraint_class.oid = pg_constraint.conrelid
      INNER JOIN pg_catalog.pg_namespace pg_constraint_namespace
        ON pg_constraint_namespace.oid = connamespace
      JOIN information_schema.columns
        ON columns.table_schema = nspname
        AND columns.table_name = pg_constraint_class.relname
        AND columns.ordinal_position = ANY(pg_constraint.conkey)
        WHERE
          contype = 'c'
          AND nspname != 'information_schema'
          AND nspname != 'postgis'
          AND left(nspname, 3) != 'pg_'
        GROUP BY
          pg_constraint.oid,
          nspname,
          pg_constraint_class.relname,
          conname;
  SQL
  connection.exec(<<~SQL)
    CREATE UNIQUE INDEX dynamic_migrations_validations_cache_index ON #{Postgres.cache_schema_name}.dynamic_migrations_validations_cache (schema_name, table_name, validation_name);
  SQL
  connection.exec(<<~SQL)
    COMMENT ON MATERIALIZED VIEW #{Postgres.cache_schema_name}.dynamic_migrations_validations_cache IS 'A cached representation of the database validations. This is used by the dynamic migrations library and is created automatically and updated automatically after migrations have run.';
  SQL
end

#fetch_validations ⇒ Object

fetch all columns from the database and build and return a useful hash representing the validations of your database



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# File 'lib/dynamic_migrations/postgres/server/database/validations_loader.rb', line 58

def fetch_validations
  begin
    rows = connection.exec(<<~SQL)
      SELECT * FROM #{Postgres.cache_schema_name}.dynamic_migrations_validations_cache
    SQL
  rescue PG::UndefinedTable
    create_database_validations_cache
    rows = connection.exec(<<~SQL)
      SELECT * FROM #{Postgres.cache_schema_name}.dynamic_migrations_validations_cache
    SQL
  end

  schemas = {}
  rows.each do |row|
    schema_name = row["schema_name"].to_sym
    schema = schemas[schema_name] ||= {}

    table_name = row["table_name"].to_sym
    table = schema[table_name] ||= {}

    validation_name = row["validation_name"].to_sym

    matches = row["check_clause"].match(/\ACHECK \((?<inner_clause>.*)\)\z/)
    if matches.nil?
      raise StandardError, "Unparsable check_clause #{row["check_clause"]}"
    end
    check_clause = matches[:inner_clause]

    table[validation_name] = {
      columns: row["columns"].gsub(/\A\{/, "").gsub(/\}\Z/, "").split(",").map { |column_name| column_name.to_sym },
      check_clause: check_clause,
      description: row["description"],
      deferrable: row["deferrable"] == "TRUE",
      initially_deferred: row["initially_deferred"] == "TRUE"
    }
  end
  schemas
end

#refresh_database_validations_cache ⇒ Object 



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# File 'lib/dynamic_migrations/postgres/server/database/validations_loader.rb', line 48

def refresh_database_validations_cache
  connection.exec(<<~SQL)
    REFRESH MATERIALIZED VIEW #{Postgres.cache_schema_name}.dynamic_migrations_validations_cache
  SQL
rescue PG::UndefinedTable
  create_database_validations_cache
end