CODEWITHSUNDEEP
javascripttypescassandranumbersmetadata
Alon Weissfeld
Alon Weissfeld

Reputation: 1325

Cassandra code for column types?

I'm having a problem understanding the code system cassandra provides for each column type. I'm using Node.js driver ('cassandra-driver') and I'm using the client.metadata.getTable to retrieve metadata information:

client.metadata.getTable( 'dev', 'artists', function ( err, table ) {
    if ( !err ) {
        table.columns.forEach( function ( column ) {
            console.log( column );
        });
    }
});

Example column result:

{ name: 'genre',
  type: 
   { code: 13,
     info: null,
     options: { reversed: false, frozen: false } } }

When I created the table, I set 'genre' as varchar (so I'm guessing 13 = varchar). What I'm trying to understand is the connection between all the code numbers and their type, without guessing. I haven't found anything regarding this subject in the docs nor online. Any thoughts?

Upvotes: 2

Views: 361

Answers (1)

HashtagMarkus
HashtagMarkus

Reputation: 1661

Have a look at nodejs-driver/lib/types/index.js ( Node.js sources on gitHub. )

var dataTypes = {
  custom:     0x0000,
  ascii:      0x0001,
  bigint:     0x0002,
  blob:       0x0003,
  boolean:    0x0004,
  counter:    0x0005,
  decimal:    0x0006,
  double:     0x0007,
  float:      0x0008,
  int:        0x0009,
  text:       0x000a,
  timestamp:  0x000b,
  uuid:       0x000c,
  varchar:    0x000d,
  varint:     0x000e,
  timeuuid:   0x000f,
  inet:       0x0010,
  date:       0x0011,
  time:       0x0012,
  smallint:   0x0013,
  tinyint:    0x0014,
  list:       0x0020,
  map:        0x0021,
  set:        0x0022,
  udt:        0x0030,
  tuple:      0x0031,

So you guessed right, 13 equals varchar.

edit Those values are hexadezimal representations. For example varchar 0x000d (hex) equals 13 (dec). But actually I don't really know why they are using hex here instead of dec. Basically they are using values from custom:0 (dec) to tuple:25 (dec) for defining those types.

The google calculator can help you with the convertion between hex and dec. Example: https://www.google.de/#q=0x000d+to+decimal

Upvotes: 2

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