Module: PgPower::ConnectionAdapters::PostgreSQLAdapter::CommentMethods

Included in:
PgPower::ConnectionAdapters::PostgreSQLAdapter
Defined in:
lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb

Overview

Provides methods to extend ActiveRecord::ConnectionAdapters::PostgreSQLAdapter to support comments feature.

Instance Method Summary collapse

Instance Method Details

#comments(table_name) ⇒ Object

Fetches all comments related to passed table. I returns table comment and column comments as well.

Example

comments("users") # => [[ ""    , "Comment on table"       ],
                        ["id"   , "Comment on id column"   ],
                        ["email", "Comment on email column"]]



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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 77

def comments(table_name)
  relation_name, schema_name = table_name.split(".", 2).reverse
  schema_name ||= :public

  com = select_all <<-SQL
    SELECT a.attname AS column_name, d.description AS comment
    FROM pg_description d
      JOIN pg_class c on c.oid = d.objoid
      LEFT OUTER JOIN pg_attribute a ON c.oid = a.attrelid AND a.attnum = d.objsubid
      JOIN pg_namespace ON c.relnamespace = pg_namespace.oid
    WHERE c.relkind = 'r' AND c.relname = '#{relation_name}' AND
      pg_namespace.nspname = '#{schema_name}'
  SQL
  com.map do |row|
    [ row['column_name'], row['comment'] ]
  end
end

#index_comments ⇒ Object

Fetches index comments returns an Array of Arrays, each element representing a single index with comment as

[ 'schema_name', 'index_name', 'comment' ]



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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 98

def index_comments
  query =  <<-SQL
    SELECT c.relname AS index_name, d.description AS comment, pg_namespace.nspname AS schema_name
    FROM pg_description d
    JOIN pg_class c ON c.oid = d.objoid
    JOIN pg_namespace ON c.relnamespace = pg_namespace.oid
    WHERE c.relkind = 'i'
    ORDER BY schema_name, index_name
  SQL

  com = select_all(query)

  com.map do |row|
    [ row['schema_name'], row['index_name'], row['comment'] ]
  end
end

#remove_column_comment(table_name, column_name) ⇒ Object

Executes SQL to remove comment on column.

Parameters:

  • table_name (String, Symbol)
  • column_name (String, Symbol) 


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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 52

def remove_column_comment(table_name, column_name)
  sql = "COMMENT ON COLUMN #{quote_table_name(table_name)}.#{quote_column_name(column_name)} IS NULL;"
  execute sql
end

#remove_column_comments(table_name, *column_names) ⇒ Object

Remove comments on passed table columns.



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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 58

def remove_column_comments(table_name, *column_names)
  column_names.each do |column_name|
    remove_column_comment table_name, column_name
  end
end

#remove_index_comment(index_name) ⇒ Object

Removes any comment from the given index

Parameters:

  • index_name (String, Symbol) —

    The name of the index



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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 66

def remove_index_comment(index_name)
  sql = "COMMENT ON INDEX #{quote_string(index_name)} IS NULL;"
  execute sql
end

#remove_table_comment(table_name) ⇒ Object

Executes SQL to remove comment on passed table.

Parameters:

  • table_name (String, Symbol) 


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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 44

def remove_table_comment(table_name)
  sql = "COMMENT ON TABLE #{quote_table_name(table_name)} IS NULL;"
  execute sql
end

#set_column_comment(table_name, column_name, comment) ⇒ Object

Executes SQL to set comment on column.

Parameters:

  • table_name (String, Symbol)
  • column_name (String, Symbol)
  • comment (String) 


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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 20

def set_column_comment(table_name, column_name, comment)
  sql = "COMMENT ON COLUMN #{quote_table_name(table_name)}.#{quote_column_name(column_name)} IS $$#{comment}$$;"
  execute sql
end

#set_column_comments(table_name, comments) ⇒ Object

Sets comments on columns of passed table.

Parameters:

  • table_name (String, Symbol)
  • comments (Hash) —

    every key is a column name and value is a comment.



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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 28

def set_column_comments(table_name, comments)
  comments.each_pair do |column_name, comment|
    set_column_comment table_name, column_name, comment
  end
end

#set_index_comment(index_name, comment) ⇒ Object

Sets the given comment on the given index

Parameters:

  • index_name (String, Symbol) —

    The name of the index

  • comment (String, Symbol) —

    The comment to set on the index



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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 37

def set_index_comment(index_name, comment)
  sql = "COMMENT ON INDEX #{quote_string(index_name)} IS $$#{comment}$$;"
  execute sql
end

#set_table_comment(table_name, comment) ⇒ Object

Executes SQL to set comment on table

Parameters:

  • table_name (String, Symbol) —

    name of table to set a comment on

  • comment (String) 


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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 11

def set_table_comment(table_name, comment)
  sql = "COMMENT ON TABLE #{quote_table_name(table_name)} IS $$#{comment}$$;"
  execute sql
end

#supports_comments? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pg_power/connection_adapters/postgresql_adapter/comment_methods.rb', line 4

def supports_comments?
  true
end