Module: Sequel::MSSQL::DatabaseMethods

Includes:
Database::SplitAlterTable
Included in:
ADO::MSSQL::DatabaseMethods, JDBC::MSSQL::DatabaseMethods, ODBC::MSSQL::DatabaseMethods, TinyTDS::Database
Defined in:
lib/sequel/adapters/shared/mssql.rb

Constant Summary collapse

FOREIGN_KEY_ACTION_MAP = 
{0 => :no_action, 1 => :cascade, 2 => :set_null, 3 => :set_default}.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#like_without_collate ⇒ Object

Whether to use LIKE without COLLATE Latin1_General_CS_AS. Skipping the COLLATE can significantly increase performance in some cases.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 29

def like_without_collate
  @like_without_collate
end

#mssql_unicode_strings ⇒ Object

Whether to use N” to quote strings, which allows unicode characters inside the strings. True by default for compatibility, can be set to false for a possible performance increase. This sets the default for all datasets created from this Database object.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 25

def mssql_unicode_strings
  @mssql_unicode_strings
end

Instance Method Details

#call_mssql_sproc(name, opts = OPTS) ⇒ Object

Execute the given stored procedure with the given name.

Options:

:args

Arguments to stored procedure. For named arguments, this should be a hash keyed by argument name. For unnamed arguments, this should be an array. Output parameters to the function are specified using :output. You can also name output parameters and provide a type by using an array containing :output, the type name, and the parameter name.

:server

The server/shard on which to execute the procedure.

This method returns a single hash with the following keys:

:result

The result code of the stored procedure

:numrows

The number of rows affected by the stored procedure

output params

Values for any output paramters, using the name given for the output parameter

Because Sequel datasets only support a single result set per query, and retrieving the result code and number of rows requires a query, this does not support stored procedures which also return result sets. To handle such stored procedures, you should drop down to the connection/driver level by using Sequel::Database#synchronize to get access to the underlying connection object.

Examples:

DB.call_mssql_sproc(:SequelTest, {args: ['input arg', :output]})
DB.call_mssql_sproc(:SequelTest, {args: ['input arg', [:output, 'int', 'varname']]})

named params:
DB.call_mssql_sproc(:SequelTest, args: {
  'input_arg1_name' => 'input arg1 value',
  'input_arg2_name' => 'input arg2 value',
  'output_arg_name' => [:output, 'int', 'varname']
})



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# File 'lib/sequel/adapters/shared/mssql.rb', line 64

def call_mssql_sproc(name, opts=OPTS)
  args = opts[:args] || []
  names = ['@RC AS RESULT', '@@ROWCOUNT AS NUMROWS']
  declarations = ['@RC int']
  values = []

  if args.is_a?(Hash)
    named_args = true
    args = args.to_a
    method = :each
  else
    method = :each_with_index
  end

  args.public_send(method) do |v, i|
    if named_args
      k = v
      v, type, select = i
      raise Error, "must provide output parameter name when using output parameters with named arguments" if v == :output && !select
    else
      v, type, select = v
    end

    if v == :output
      type ||= "nvarchar(max)"
      if named_args
        varname = select
      else
        varname = "var#{i}"
        select ||= varname
      end
      names << "@#{varname} AS #{quote_identifier(select)}"
      declarations << "@#{varname} #{type}"
      value = "@#{varname} OUTPUT"
    else
      value = literal(v)
    end

    if named_args
      value = "@#{k}=#{value}"
    end

    values << value
  end

  sql = "DECLARE #{declarations.join(', ')}; EXECUTE @RC = #{name} #{values.join(', ')}; SELECT #{names.join(', ')}"

  ds = dataset.with_sql(sql)
  ds = ds.server(opts[:server]) if opts[:server]
  ds.first
end

#database_type ⇒ Object 



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# File 'lib/sequel/adapters/shared/mssql.rb', line 116

def database_type
  :mssql
end

#foreign_key_list(table, opts = OPTS) ⇒ Object

Return foreign key information using the system views, including :name, :on_delete, and :on_update entries in the hashes.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 127

def foreign_key_list(table, opts=OPTS)
  m = output_identifier_meth
  im = input_identifier_meth
  schema, table = schema_and_table(table)
  current_schema = m.call(get(Sequel.function('schema_name')))
  fk_action_map = FOREIGN_KEY_ACTION_MAP
  fk = Sequel[:fk]
  fkc = Sequel[:fkc]
  ds = metadata_dataset.from(Sequel.lit('[sys].[foreign_keys]').as(:fk)).
    join(Sequel.lit('[sys].[foreign_key_columns]').as(:fkc), :constraint_object_id => :object_id).
    join(Sequel.lit('[sys].[all_columns]').as(:pc), :object_id => fkc[:parent_object_id],     :column_id => fkc[:parent_column_id]).
    join(Sequel.lit('[sys].[all_columns]').as(:rc), :object_id => fkc[:referenced_object_id], :column_id => fkc[:referenced_column_id]).
    where{{object_schema_name(fk[:parent_object_id]) => im.call(schema || current_schema)}}.
    where{{object_name(fk[:parent_object_id]) => im.call(table)}}.
    select{[fk[:name], 
            fk[:delete_referential_action], 
            fk[:update_referential_action], 
            pc[:name].as(:column), 
            rc[:name].as(:referenced_column), 
            object_schema_name(fk[:referenced_object_id]).as(:schema), 
            object_name(fk[:referenced_object_id]).as(:table)]}.
    order(fk[:name], fkc[:constraint_column_id])
  h = {}
  ds.each do |row|
    if r = h[row[:name]]
      r[:columns] << m.call(row[:column])
      r[:key] << m.call(row[:referenced_column])
    else
      referenced_schema = m.call(row[:schema])
      referenced_table = m.call(row[:table])
      h[row[:name]] = { :name      => m.call(row[:name]), 
                        :table     => (referenced_schema == current_schema) ? referenced_table : Sequel.qualify(referenced_schema, referenced_table),
                        :columns   => [m.call(row[:column])], 
                        :key       => [m.call(row[:referenced_column])], 
                        :on_update => fk_action_map[row[:update_referential_action]], 
                        :on_delete => fk_action_map[row[:delete_referential_action]] }
    end
  end
  h.values
end

#freeze ⇒ Object 



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# File 'lib/sequel/adapters/shared/mssql.rb', line 168

def freeze
  server_version
  super
end

#global_index_namespace? ⇒ Boolean

Microsoft SQL Server namespaces indexes per table.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 121

def global_index_namespace?
  false
end

#indexes(table, opts = OPTS) ⇒ Object

Use the system tables to get index information



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# File 'lib/sequel/adapters/shared/mssql.rb', line 174

def indexes(table, opts=OPTS)
  m = output_identifier_meth
  im = input_identifier_meth
  indexes = {}
  table = table.value if table.is_a?(Sequel::SQL::Identifier)
  i = Sequel[:i]
  ds = metadata_dataset.from(Sequel.lit('[sys].[tables]').as(:t)).
   join(Sequel.lit('[sys].[indexes]').as(:i), :object_id=>:object_id).
   join(Sequel.lit('[sys].[index_columns]').as(:ic), :object_id=>:object_id, :index_id=>:index_id).
   join(Sequel.lit('[sys].[columns]').as(:c), :object_id=>:object_id, :column_id=>:column_id).
   select(i[:name], i[:is_unique], Sequel[:c][:name].as(:column)).
   where{{t[:name]=>im.call(table)}}.
   where(i[:is_primary_key]=>0, i[:is_disabled]=>0).
   order(i[:name], Sequel[:ic][:index_column_id])

  if supports_partial_indexes?
    ds = ds.where(i[:has_filter]=>0)
  end

  ds.each do |r|
    index = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>(r[:is_unique] && r[:is_unique]!=0)}
    index[:columns] << m.call(r[:column])
  end
  indexes
end

#server_version(server = nil) ⇒ Object

The version of the MSSQL server, as an integer (e.g. 10001600 for SQL Server 2008 Express).



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# File 'lib/sequel/adapters/shared/mssql.rb', line 202

def server_version(server=nil)
  return @server_version if @server_version
  if @opts[:server_version]
    return @server_version = Integer(@opts[:server_version])
  end
  @server_version = synchronize(server) do |conn|
    (conn.server_version rescue nil) if conn.respond_to?(:server_version)
  end
  unless @server_version
    m = /^(\d+)\.(\d+)\.(\d+)/.match(fetch("SELECT CAST(SERVERPROPERTY('ProductVersion') AS varchar)").single_value.to_s)
    @server_version = (m[1].to_i * 1000000) + (m[2].to_i * 10000) + m[3].to_i
  end
  @server_version
end

#supports_partial_indexes? ⇒ Boolean

MSSQL 2008+ supports partial indexes.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 218

def supports_partial_indexes?
  dataset.send(:is_2008_or_later?)
end

#supports_savepoints? ⇒ Boolean

MSSQL supports savepoints, though it doesn’t support releasing them

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 223

def supports_savepoints?
  true
end

#supports_transaction_isolation_levels? ⇒ Boolean

MSSQL supports transaction isolation levels

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 228

def supports_transaction_isolation_levels?
  true
end

#supports_transactional_ddl? ⇒ Boolean

MSSQL supports transaction DDL statements.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 233

def supports_transactional_ddl?
  true
end

#tables(opts = OPTS) ⇒ Object

Microsoft SQL Server supports using the INFORMATION_SCHEMA to get information on tables.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 239

def tables(opts=OPTS)
  information_schema_tables('BASE TABLE', opts)
end

#views(opts = OPTS) ⇒ Object

Microsoft SQL Server supports using the INFORMATION_SCHEMA to get information on views.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 245

def views(opts=OPTS)
  information_schema_tables('VIEW', opts)
end

#with_advisory_lock(lock_id, opts = OPTS) ⇒ Object

Attempt to acquire an exclusive advisory lock with the given lock_id (which will be converted to a string). If successful, yield to the block, then release the advisory lock when the block exits. If unsuccessful, raise a Sequel::AdvisoryLockError.

Options:

:wait

Do not raise an error, instead, wait until the advisory lock can be acquired.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 255

def with_advisory_lock(lock_id, opts=OPTS)
  lock_id = lock_id.to_s
  timeout = opts[:wait] ? -1 : 0
  server = opts[:server]

  synchronize(server) do
    begin
      res = call_mssql_sproc(:sp_getapplock, :server=>server, :args=>{'Resource'=>lock_id, 'LockTimeout'=>timeout, 'LockMode'=>'Exclusive', 'LockOwner'=>'Session'})

      unless locked = res[:result] >= 0
          raise AdvisoryLockError, "unable to acquire advisory lock #{lock_id.inspect}"
      end

      yield
    ensure
      if locked
        call_mssql_sproc(:sp_releaseapplock, :server=>server, :args=>{'Resource'=>lock_id, 'LockOwner'=>'Session'})
      end
    end
  end
end