Several UAF
functions take a formula as input. A formula is a string (VARCHAR(64000)) that follows these rules:
- The formula is enclosed in single or double quotation marks.
- The formula starts with "Y =".
Y is the response variable (also called the result parameter, dependent variable, or forecasting variable). It must be named Y or y. It corresponds to the first field referenced in SERIES_SPEC(PAYLOAD(FIELDS())).
- After "Y =" the formula has a SQL arithmetic expression composed of coefficients, explanatory variables, numeric constants, numeric variables, arithmetic operators, arithmetic functions, trigonometric functions, and parentheses.
- Each coefficient follows these rules:
- It appears immediately before a multiplication operator (*), which appears immediately before an explanatory variable.
- It is either a numeric constant or a numeric variable.If it is a numeric variable:
- It has a Teradata UNICODE object name that contains no escape character or quotation mark.
- Its name is case-insensitive.
- The function estimates its value.
- It appears in the formula only once.
- Each explanatory variable follows these rules:
- Its position in the formula is significant: The nth explanatory variable corresponds to the nth field referenced in SERIES_SPEC(PAYLOAD(FIELDS())).
- It has a Teradata-supported name label.
- It can appear in the formula multiple times.
For supported arithmetic operators, arithmetic functions, trigonometric functions, and general information about SQL arithmetic expression structure, see Teradata® Database SQL Functions, Operators, Expressions, and Predicates, B035-1145.
Example: Numeric Variable Coefficients
Y = d + a*X1 + b*X2 + c*(exp(X3) * cos(X2))
d is a numeric variable.
a, b, and c are numeric variable coefficients. The function estimates their values.
X1, X2, and X3 are explanatory variables.
Example: Numeric Constant Coefficients
Y = 89 + 6*X1 + 2.99*X1**2 + exp(X2)
89 is a numeric constant.
2, 6 and 2.99 are numeric constant coefficients.
X1 and X2 are explanatory variables.