Class: Migrate::Storage::Postgres

Inherits:
DB
  • Object
show all
Defined in:
lib/migrate/storage/postgres.rb

Instance Attribute Summary

Attributes inherited from DB

#config

Instance Method Summary collapse

Methods inherited from DB

#current_version, #delete, #get_migration, #highest_version, #list_migrations, #log_down, #log_up, #lowest_version, #migrations_from, #migrations_range, #new_migration, #next_version, #prev_version, #print, #type, #version_exists?

Constructor Details

#initialize(*args) ⇒ Postgres

Returns a new instance of Postgres.



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# File 'lib/migrate/storage/postgres.rb', line 7

def initialize(*args)
  super
  @conn = PG.connect({
    dbname: @config.database,
    host: @config.host,
    user: @config.user,
    password: @config.password,
  })
end

Instance Method Details

#create_tables ⇒ Object 



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# File 'lib/migrate/storage/postgres.rb', line 37

def create_tables
  Log.info("Creating version table")
  self.exec_sql <<-eos
  CREATE TABLE #{@config.version_info}
  (
    version SERIAL PRIMARY KEY NOT NULL,
    description TEXT,
    created_date TIMESTAMP WITH TIME ZONE NOT NULL,
    last_up TIMESTAMP WITH TIME ZONE,
    last_down TIMESTAMP WITH TIME ZONE
  );
  CREATE UNIQUE INDEX #{@config.version_info}_version_uindex ON #{@config.version_info} (version);

  CREATE TABLE #{@config.version_number}
  (
    version INT PRIMARY KEY NOT NULL
  );

  INSERT INTO #{@config.version_number} VALUES(0);
  eos
  Log.success("Version table created")
end

#exec_sql(sql) ⇒ Object 



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# File 'lib/migrate/storage/postgres.rb', line 69

def exec_sql(sql)
  @tx.exec sql
end

#extract_version(results) ⇒ Object 



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# File 'lib/migrate/storage/postgres.rb', line 61

def extract_version(results)
  if results && results.count > 0
    results[0]["version"]
  else
    raise VersionNotFound
  end
end

#has_tx ⇒ Object 



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# File 'lib/migrate/storage/postgres.rb', line 73

def has_tx
  @tx != nil
end

#tables_exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/migrate/storage/postgres.rb', line 17

def tables_exists?
  vi = self.exec_sql <<-eos
    SELECT EXISTS (
      SELECT 1
      FROM information_schema.tables
      WHERE table_name = '#{@config.version_info}'
    );
  eos

  vn = self.exec_sql <<-eos
    SELECT EXISTS (
      SELECT 1
      FROM information_schema.tables
      WHERE table_name = '#{@config.version_number}'
    );
  eos

  vi[0]["exists"].to_b && vn[0]["exists"].to_b
end

#tx ⇒ Object 



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# File 'lib/migrate/storage/postgres.rb', line 77

def tx
  if has_tx
    yield
  else
    begin
      @conn.transaction do |tx|
        @tx = tx
        yield
      end
    ensure
      @tx = nil
    end
  end
end