Class: Sequel::Extension::PgComment::SqlGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/sequel/extensions/pg_comment/sql_generator.rb

Overview

:nodoc: Generate SQL to set a comment.

Direct Known Subclasses

PrefixSqlGenerator, TableObjectSqlGenerator

Constant Summary collapse

OBJECT_TYPES =

The PostgreSQL object types which this class knows how to generate comment SQL for.

%w{AGGREGATE
             CAST
             COLLATION
             CONVERSION
             DATABASE
             DOMAIN
	EXTENSION
	EVENT\ TRIGGER
	FOREIGN\ DATA\ WRAPPER
	FOREIGN\ TABLE
	FUNCTION
	INDEX
	LARGE\ OBJECT
	MATERIALIZED\ VIEW
	OPERATOR
	OPERATOR\ CLASS
	OPERATOR\ FAMILY
	PROCEDURAL\ LANGUAGE
	LANGUAGE
	ROLE
	SCHEMA
	SEQUENCE
	SERVER
	TABLE
	TABLESPACE
	TEXT\	SEARCH\ CONFIGURATION
	TEXT\ SEARCH\ DICTIONARY
	TEXT\ SEARCH\ PARSER
	TEXT\ SEARCH\ TEMPLATE
	TYPE
	VIEW
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(object_type, object_name, comment) ⇒ SqlGenerator

Spawn a new SqlGenerator.

See Also:

  • Sequel::Extension::PgComment::SqlGenerator.{{.create}


119
120
121
122
123
 
# File 'lib/sequel/extensions/pg_comment/sql_generator.rb', line 119

def initialize(object_type, object_name, comment)
	@object_type = object_type.to_s.upcase.gsub('_', ' ')
	@object_name = object_name
	@comment     = comment
end

Instance Attribute Details

#comment ⇒ Object (readonly)

The comment.



113
114
115
 
# File 'lib/sequel/extensions/pg_comment/sql_generator.rb', line 113

def comment
  @comment
end

#object_name ⇒ Object (readonly)

The raw (might-be-a-symbol, might-be-a-string) object name that was passed to us originally.



110
111
112
 
# File 'lib/sequel/extensions/pg_comment/sql_generator.rb', line 110

def object_name
  @object_name
end

#object_type ⇒ Object (readonly)

The canonicalised string (that is, all-uppercase, with words separated by spaces) for the object type of this SQL generator.



105
106
107
 
# File 'lib/sequel/extensions/pg_comment/sql_generator.rb', line 105

def object_type
  @object_type
end

Class Method Details

.create(object_type, object_name, comment) ⇒ SqlGenerator

Find the correct class for a given object type, and instantiate a new one of them.

Parameters:

  • object_type (String, Symbol) —

    The type of object we're going to comment on. Strings and symbols are both fine, and any case is fine, too. Any underscores get turned into spaces. Apart from that, it needs to be the exact name that PostgreSQL uses for the given type.

  • object_name (String, Symbol) —

    The name of the database object to set the comment on. A string is considered "already quoted", and hence is not escaped any further. A symbol is run through the usual Sequel identifier escaping code before being unleashed on the world.

  • comment (String) —

    The comment to set.

Returns:

  • (SqlGenerator) —

    Some sort of SqlGenerator object, or a subclass.

Raises:

  • (ArgumentError) —

    if you passed in an object_type that we don't know about.



63
64
65
66
67
68
69
70
71
72
 
# File 'lib/sequel/extensions/pg_comment/sql_generator.rb', line 63

def self.create(object_type, object_name, comment)
	generators.each do |gclass|
		if gclass.handles?(object_type)
			return gclass.new(object_type, object_name, comment)
		end
	end

	raise ArgumentError,
	      "Unrecognised object type #{object_type.inspect}"
end

.handles?(object_type) ⇒ TrueClass, FalseClass

Return whether or not this class supports the specified object type.

Parameters:

  • object_type (String, Symbol) —

    @see create

Returns:

  • (TrueClass, FalseClass) —

    whether or not this class can handle the object type you passed.



81
82
83
 
# File 'lib/sequel/extensions/pg_comment/sql_generator.rb', line 81

def self.handles?(object_type)
	self.const_get(:OBJECT_TYPES).include?(object_type.to_s.upcase.gsub('_', ' '))
end

Instance Method Details

#generate ⇒ String

SQL to set a comment on the object of our affection.

Returns:

  • (String) —

    The SQL needed to set the comment.



129
130
131
132
133
134
135
136
137
138
 
# File 'lib/sequel/extensions/pg_comment/sql_generator.rb', line 129

def generate
	quoted_object_name = case object_name
	when Symbol
		literal object_name
	else
		object_name
	end
		
	"COMMENT ON #{object_type} #{quoted_object_name} IS #{literal comment.to_s}"
end