Help Center> GaussDB> Distributed_2.x> SQL Reference> Data Type> Data Types Used by the Ledger Database
Updated on 2023-10-23 GMT+08:00
View PDF

Data Types Used by the Ledger Database

The ledger database uses the hash16 data type to store row-level hash digests or table-level hash digests, and uses the hash32 data type to store global hash digests or history table verification hashes. (The current feature is a lab feature. Contact Huawei engineers for technical support before using it.)

Table 1 Hash type of the ledger database

Name

Description

Storage Space

Range

HASH16

Stored as an unsigned 64-bit integer

8 bytes

0 to +18446744073709551615

HASH32

Stored as an unsigned integer array of 16 elements

16 bytes

Value range of an unsigned integer array of 16 elements

The hash16 data type is used to store row-level or table-level hash digests in the ledger database. After obtaining the hash sequence of a 16-character hexadecimal string, the system invokes the hash16in function to convert the sequence into an unsigned 64-bit integer and stores the integer in a hash16 variable. Example:

Hexadecimal string: e697da2eaa3a775b; corresponding 64-bit unsigned integer: 16615989244166043483
Hexadecimal string: ffffffffffffffff; corresponding 64-bit unsigned integer: 18446744073709551615

The hash32 data type is used to store the global hash digest or history table verification hash in the ledger database. After obtaining the hash sequence of a 32-character hexadecimal string, the system invokes the hash32in function to convert the sequence to an unsigned integer array of 16 elements. Example:

Hexadecimal string: 685847ed1fe38e18f6b0e2b18c00edee
Corresponding hash32 array: [104,88,71,237,31,227,142,24,246,176,226,177,140,0,237,238]
Parent topic: Data Type