database
  name
  ---
  db-engine build level
  
table
  name                char[64]     table name
  ----
  fileheapname        char[256]    name for fileheap file
  attributes          uint16       # attributes
  (recordsize)        uint32       size of (fixed records, in bytes)
  
attribute
  tablename           char[64]     table name  FK(table.name)
  name                char[64]     attribute name
  basictype           char[32]     basic type name (s/uint8/16/32, char, varchar, binary, decimal)
  (length)            uint32       maximum size of attribute
  ---
  basictype_i         uint16       basic type binary coded (1..~13)
  attr_index          uint16       index(order) of attribute
  ---
  MinMin              binary[64]   lowest possible minimum value
  MaxMin              binary[64]   highest possible minimum value
  MinMax              binary[64]   lowest possible maximum value
  MaxMax              binary[64]   highest possible maximum value
  Median              binary[64]   median value

candidatekey
  tablename           char[64]     table name  FK(table.name)
  keyname             char[64]     key name

candidatekeyattribute
  tablename           char[64]     table name FK(candidatekey.tablename)
  keyname             char[64]     key name 
  attrname            char[64]     attribute name FK(attribute.name)

sequence
  name                char[64]     sequence name
  current_value       uint32       current value of sequence
  min                 uint32       min value
  max                 uint32       max value
  wrap                bool         wrap around?

---
index
  tablename           char[64]     table name
  type                uint16       (sequential, lookup, secondary, kd)
  fileheapname1       char[256]    name of fileheap containing index
  fileheapname2       char[256]
  
indexattribute
  name                char[64]     name of index
  attr_order          uint16       order of index attribute in index
  attrname            char[64]     attribute name


lookup indexes:
  extendible hashing
  fixedfileheap (fileheapname1) containing array of recids
  varfileheap contains records:
    next_recid
    attr[] (binary)
    
secondary indexes:
  varfileheap (2 attrs)
   attr1value1  --->  attr2value1   ---> recidblock1
   |                  |                  |
   V                  V                  V
   attr1value2        attr2value2        recidblock2
   |
   V
   attr1value3

kd index:
  varfileheap
    parent_recid  recid
    index_index
    key
    less_recid
    equal_recid
    greater_recid
    equal_final