Class: ActiveRecord::ConnectionAdapters::SchemaCache

Inherits:
Object
  • Object
show all
Defined in:
activerecord/lib/active_record/connection_adapters/schema_cache.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(conn) ⇒ SchemaCache

Returns a new instance of SchemaCache


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 7

def initialize(conn)
  @connection = conn
  @tables     = {}

  @columns = Hash.new do |h, table_name|
    h[table_name] = conn.columns(table_name, "#{table_name} Columns")
  end

  @columns_hash = Hash.new do |h, table_name|
    h[table_name] = Hash[columns[table_name].map { |col|
      [col.name, col]
    }]
  end

  @primary_keys = Hash.new do |h, table_name|
    h[table_name] = table_exists?(table_name) ? conn.primary_key(table_name) : nil
  end
end

Instance Attribute Details

#columnsObject (readonly)

Returns the value of attribute columns


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 4

def columns
  @columns
end

#columns_hashObject (readonly)

Returns the value of attribute columns_hash


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 4

def columns_hash
  @columns_hash
end

#connectionObject (readonly)

Returns the value of attribute connection


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 5

def connection
  @connection
end

#primary_keysObject (readonly)

Returns the value of attribute primary_keys


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 4

def primary_keys
  @primary_keys
end

#tablesObject (readonly)

Returns the value of attribute tables


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 4

def tables
  @tables
end

Instance Method Details

#clear!Object

Clears out internal caches


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 34

def clear!
  @columns.clear
  @columns_hash.clear
  @primary_keys.clear
  @tables.clear
end

#clear_table_cache!(table_name) ⇒ Object

Clear out internal caches for table with table_name.


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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 42

def clear_table_cache!(table_name)
  @columns.delete table_name
  @columns_hash.delete table_name
  @primary_keys.delete table_name
  @tables.delete table_name
end

#table_exists?(name) ⇒ Boolean

A cached lookup for table existence.

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/schema_cache.rb', line 27

def table_exists?(name)
  return @tables[name] if @tables.key? name

  @tables[name] = connection.table_exists?(name)
end