Class: BtrieveSchema

Inherits:
Object
  • Object
show all
Includes:
Btrieve
Defined in:
lib/btrieve/btrieve_schema.rb

Overview

Represents the btrieve schema (DDF files) of a particular BTR database.

Constant Summary collapse

CHAR =

Datatypes used to transact with the BTR engine.

{ :name=>'CHAR', :unpacker=>'a', :size=>1 }
TINYINT = 
{ :name=>'TINYINT', :unpacker=>'c', :size=>1 }
SMALLINT = 
{ :name=>'SMALLINT', :unpacker=>'s', :size=>1 }
INTEGER = 
{ :name=>'INTEGER', :unpacker=>'i', :size=>1 }
REAL = 
{ :name=>'REAL', :unpacker=>'f', :size=>1 }
DOUBLE = 
{ :name=>'DOUBLE', :unpacker=>'d', :size=>1 }
DATE =

day month year

{ :name=>'DATE', :unpacker=>'ccs', :size=>4 }
TIME =

100th sec min hour

{ :name=>'TIME', :unpacker=>'cccc', :size=>4 }
BIT = 
{ :name=>'BIT', :unpacker=>'c', :size=>1 }
VARCHAR = 
{ :name=>'VARCHAR', :unpacker=>'A', :size=>1 }
LONGVARCHAR = 
{ :name=>'LONGVARCHAR', :unpacker=>'A', :size=>1 }
UTINYINT = 
{ :name=>'UTINYINT', :unpacker=>'C', :size=>1, :size=>1 }
USMALLINT = 
{ :name=>'USMALLINT', :unpacker=>'S', :size=>1 }
UINTEGER = 
{ :name=>'UINTEGER', :unpacker=>'I', :size=>1 }
UBIGINT = 
{ :name=>'UBIGINT', :unpacker=>'Q', :size=>1 }
SIZEOF =

Array of all datatypes supported by the BTR engine.

{'a'=>1, 'c'=>1, 's'=>1, 'i'=>1, 'f'=>1, 'd'=>1, 'ccs'=>4, 'cccc'=>4, 'A'=>1, 'C'=>1, 'S'=>1, 'I'=>1, 'Q'=>1}

Constants included from BtrCodes

BtrCodes::ABORT_TRANSACTION, BtrCodes::ACCELERATED_MODE, BtrCodes::BEGIN_TRANSACTION, BtrCodes::CLOSE, BtrCodes::DELETE, BtrCodes::END_TRANSACTION, BtrCodes::EOF, BtrCodes::EXCEPTION_MESSAGES, BtrCodes::EXCLUSIVE_MODE, BtrCodes::GET_DIRECT, BtrCodes::GET_EQUAL, BtrCodes::GET_EQUAL_KEY, BtrCodes::GET_FIRST, BtrCodes::GET_GREATER_THAN_OR_EQUAL, BtrCodes::GET_LESS_THAN_OR_EQUAL, BtrCodes::GET_NEXT, BtrCodes::GET_NEXT_EXTENDED, BtrCodes::GET_NEXT_KEY, BtrCodes::GET_POSITION, BtrCodes::GET_PREVIOUS, BtrCodes::INSERT, BtrCodes::KEY_NOT_FOUND, BtrCodes::LOCAL_ACCELERATED_MODE, BtrCodes::LOCAL_EXCLUSIVE_MODE, BtrCodes::LOCAL_NORMAL_MODE, BtrCodes::LOCAL_READ_ONLY_MODE, BtrCodes::MAX_DATATYPE, BtrCodes::NORMAL_MODE, BtrCodes::NO_CURRENCY_CHANGE, BtrCodes::NO_LOGICAL_CURRENCY_KEY, BtrCodes::NULL_BUFFER, BtrCodes::NULL_KEY, BtrCodes::OK, BtrCodes::OPEN, BtrCodes::POS_BLOCK_SIZE, BtrCodes::READ_ONLY_MODE, BtrCodes::RECORD_POSITION_SIZE, BtrCodes::REMOTE_ACCELERATED_MODE, BtrCodes::REMOTE_EXCLUSIVE_MODE, BtrCodes::REMOTE_NORMAL_MODE, BtrCodes::REMOTE_READ_ONLY_MODE, BtrCodes::RESET, BtrCodes::STEP_NEXT, BtrCodes::STEP_NEXT_EXTENDED, BtrCodes::STOP, BtrCodes::SYSTEM_LOG_KEY, BtrCodes::UPDATE, BtrCodes::VERIFY_MODE

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Btrieve

#btr_op, create_string_buffer

Constructor Details

#initialize ⇒ BtrieveSchema

Creates a new instance of btrieve schema for a given session.



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# File 'lib/btrieve/btrieve_schema.rb', line 27

def initialize()
  session=BtrieveSession.get_session
  if(!session.cache[:schemas_loaded])
    cache_system_table(:'x$file')
    cache_system_table(:'x$field')
    cache_system_table(:'x$index')
    session.cache[:schemas_loaded] = true
  end
end

Instance Attribute Details

#xfield_records ⇒ Object (readonly)

Returns the value of attribute xfield_records.



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# File 'lib/btrieve/btrieve_schema.rb', line 4

def xfield_records
  @xfield_records
end

#xfile_records ⇒ Object (readonly)

Returns the value of attribute xfile_records.



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# File 'lib/btrieve/btrieve_schema.rb', line 4

def xfile_records
  @xfile_records
end

Class Method Details

.readable_type(column) ⇒ Object 



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# File 'lib/btrieve/btrieve_schema.rb', line 76

def self.readable_type(column)
  c=column.to_a[0]
  btrtype = lookup(c[1][:datatype],c[1][:size])
  [:name=>c[0], :datatype=>btrtype[:name], :size=>c[1][:size]]
end

Instance Method Details

#get_table_schema(tablename) ⇒ Object

Loads the schema of a particular btrieve table.

Raises:

  • (Exception) 


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# File 'lib/btrieve/btrieve_schema.rb', line 38

def get_table_schema(tablename)
  session=BtrieveSession.get_session
  schema = nil
  xfile_index = nil
  session.cache[:'x$file'].each do |xfile|
    next unless xfile[:'xf$name'].downcase.strip.to_sym == tablename
    schema = {:filename=>xfile[:'xf$loc'].downcase.strip, :record_size=>0, :columns=>{}}
    xfile_index = xfile[:'xf$id']
    break
  end
  xfield_index = []
  session.cache[:'x$field'].each do |xfield|
    next unless xfile_index == xfield[:'xe$file']
    next unless xfield[:'xe$datatype'] < MAX_DATATYPE
    id = xfield[:'xe$id']
    name = xfield[:'xe$name'].strip.downcase
    offset = xfield[:'xe$offset']
    size = xfield[:'xe$size']
    datatype = xfield[:'xe$datatype']
    datatype = (name == 'kid - mult') ? 14 : datatype # Absolute BS line of code...  Needed for CTA-FOS
    unpacker = BtrieveSchema.unpacker(offset, datatype, size)
    schema[:columns][name.to_sym] = {:unpacker=>unpacker, :id=>id, :offset=>offset, :datatype=>datatype, :size=>size}
    xfield_index[id] = name.to_sym
  end
  session.cache[:'x$index'].each do |xindex|
    next unless xfile_index == xindex[:'xi$file']
    indices = schema[:indices] ||= []
    index = indices[xindex[:'xi$number']] ||= []
    index[xindex[:'xi$part']] = xfield_index[xindex[:'xi$field']]
    flags = schema[:index_flags] ||= []
    flags[xindex[:'xi$number']] = flags[xindex[:'xi$number']].to_i | xindex[:'xi$flags'].to_i
  end
  last_field=schema[:columns].values.sort{|a,b| a[:offset] <=> b[:offset]}.last
  schema[:record_size] = last_field[:offset]+last_field[:size]
  raise Exception.new("Unknown table '#{tablename}'.") if schema.nil?
  schema
end