immutability in multichain

Question

Hiii TEAM ,

I am checking immutability of data in multichain so, i have created chain called xyz and inside that stream is 'test' .Also i have publised data in stream using

publish test key173747265616d2064617461

txid:b209239b63a6adc2712063b376e9fa3c20c53c5d73f60a6332e9cd4b907bee92​

{ 

    "hash" : "00473f8380ace1f5ac27aba08bcdc855b33aa21f077f257dcc159a8634b63187", 

    "previousblockhash" : "0074c2a26a616e889284abb5c643552afbcad6c35a0bb92c474db15830fb3fad", 

        "nextblockhash" : "001c5ebd08cdd5281568ff7db1b08f96a3a3573237b0ecac02626300c1707392" 

} 

now i have updated data of same key key1
publish test key1 6d7920696d6d757461626c652074657374
tx id:9ef0f983313780b619f0b96427b1c4f8b1f7e005fe6ae5e2ae0fd6f56bcdf36a

{     "hash" : "00f422586204cbfe02211d5cd9639169ec54a52b0e519d912f61305b82dccad2",  

   "tx[ "cd8dffa2b4ceb34d795586928167dcd6da8925d7f65c4df7cde2a0fac0110ac4", 

 "9ef0f983313780b619f0b96427b1c4f8b1f7e005fe6ae5e2ae0fd6f56bcdf36a"   ],  

    "previousblockhash" : "000a7a202d4af3cde5c0ffdc2293d020e2c01d447d1ceb0a14c928b340d1f94c", 

    "nextblockhash" : "00ce30145953c6702c58cb2e6c171791582dc46e4d2e630dcb1a70578305363a" 

} 

But when i fetch both transaction using getblock api i am getting different different prevblockhash and nextblockhash but not in chain?

and also wanted to understand what is the difference between hash ,prevblockhash and nextblockhash?

Answer 1

These are hashes of the blocks in which groups of transactions are stored, and they are different from transaction IDs which are individual to each transaction. The information you are seeing here is for the chain of blocks representing the blockchain's contents, and immutability means that each block (and its contents) is not changed after it is formed. But there can be new blocks being added to the chain all the time, and this does not violate immutability.