Ethereum decimals
Rc20 token standard (erc20 token standard) is a standard used to create token through Ethereum. According to the erc20 specification, a smart contract can be written to create a "interchangeable token". It is not mandatory, but following this standard, the token created can interact with many exchanges, wallets, etc. it has now been widely accepted by the instry
erc20 token standard was first proposed by Ethereum developer Fabian vogelsteller in the open source community. Later, Ethereum founder vitalik (known as "V God") wrote the first version of the document, which was called "standardized contract API" at that time_ Contract_ APIs
following erc20 token standard, smart contracts can be written. The token methods it needs to implement include: optional name, symbol, decimals, balance of, transfer, transfer from, approve, and allowance. The event responses it needs to implement include transfer, approve
in addition to erc20, Ethereum also focuses on erc721. Different from erc20, erc721 is a non fungible token standard (NFT)
The general syndromes oferc20 are interchangeable and homogeneous, while the general syndromes of erc721 are not interchangeable and heterogeneous; Erc20 can be subdivided infinitely, while erc721 can not be subdivided because its minimum unit is 1
in June 2018, erc721 was officially accepted by Ethereum community and became the final standard. The popular cryptokitties followed the erc721 standard
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system
verified weight supports maximum 3-digit values
verified weight supports maximum 3-digit values
verified weight supports maximum 3-digit values
for example: data: price type P decimals 2.
defines a variable price with 2 decimal points of type P.
English; desɪ [ml] beauty [(712; dɛ sə mə l] Decimal; decimal; n. Decimals[ Others] plural: decimals Fanyi.. com
double_ Internet translation of double English; dʌ BL] beauty; dʌ bə l] Adj; Twice as many as the others; Two faced; For two persons; Vt. double; vt; To fold in half; Repetition; Vi. redouble, redouble efforts; Walk fast[ The government committed a double blunder[ Others] third person singular: Double plural: Double present participle: Double past tense: Double past participle: Double Fanyi.. com
1. Decimal (% n)
without decimal point N represents the length of the whole value
for example, decimal (4) stores the value from - 9999 to - 9999
2. Decimal (% s,% P)
this is with a decimal point.% s represents the length of the whole value and% P is the number of decimal places
for example, decimal (5,2) stores the value from - 999.99 to - 999.99
Decimal is a precise data type in MySQL. The data types in MySQL include: float, double and other imprecise data types, and decimal. Difference: for imprecise types such as float and double, approximate values are stored in dB. Decimal saves the exact original value in the form of a string
extended data
for SQL server, decimal and numeric are regarded as the same types, and they can be used to save values with decimal point and determined value. Unlike float and real, they are used to preserve approximations. Columns of this type are declared as decima [(P [, S])] or numeric [(P [, S])]. Where p is the total number of digits of the value, including the decimal part but excluding the decimal point, and S is the number of decimal places
The value ofP is called the precision of this value. For example, decimal (10,3) means that there are 7 integers and 3 decimals in total, and the precision of this example is 10 digits. Columns of this type can hold values ranging from 1038-1 to - 1038-1. The storage space occupied varies according to the accuracy. The following table shows the relationship between the accuracy of decimal type variables and the space occupied
is reced to a decimal
so
2 / 5 = 0.4
Decima (6,2) represents a number with a total length of 6 and two decimal places
for SQL server, decimal can be used to save values with decimal point and definite value, unlike float and real, which are used to save approximate values
for visual basic, decimal is a new data type in version 5, which is designed to meet the needs of precise mathematical operation. It is the largest and most accurate floating-point number type
for Excel, the decimal() function is used to convert the text representation of a number to a decimal number according to a given cardinality
extended data
data precision
decimal variables are stored as 96 bit (12 byte) unsigned integer form, signed integer form, and divided by an idempotent of 10. This variable ratio factor determines the number of digits on the right side of the decimal point, which ranges from 0 to 28. When the variable ratio factor is 0 (no decimal place), the maximum possible value is + / - 79228162514264337593543950335
When there are 28 decimal places, the maximum value is + / - 7.922816254264337593543950335, and the minimum non-zero value is + / - 0.0000000000001