Getting Started with SAND CDBMS: Using SAND CDBMS
Loading Data into Tables Using the SAND CDBMS Data Loader

Setting Up the Data Load with the Load Specification Script

Advanced Load Options: Analyzing and Manipulating Data with NDL++ Expressions

The NDL++ scripting language offers a wide variety of options for analyzing, manipulating, and converting data as it is loaded by ndlm. NDL++ provides both character string and math functions for performing data-type conversion and data analysis of specified fields. Certain kinds of data can also be generated for insertion into the target table (including current date and time, as well as a unique key for a specified group of fields). Variables can be declared to receive the output of data manipulation or analysis; these variables can then be used in statements or expressions elsewhere in the script. Conditional expressions can be used to specify courses of action that are to be taken only when certain conditions are present.

NDL++ functions can be used in the map specification (table) section and in the NULLIF, MISSINGIF, and SKIPIF clauses of ndlm import specification script files. They are typically included in the map specification to specify operations to be performed on input data. Analytical functions are useful for inclusion in variables and conditional expressions.

String Functions

The following table lists in alphabetical order the character string functions that can be used in NDL++ scripts, and provides a short description of each function along with its input and output data types. More detailed descriptions and examples are included in the NDL++ String Function Syntax and Examples section of the SAND CDBMS Tools Reference Guide.

Function	Description
CMP()	Compares the ASCII values of two strings
DATE()	Returns the current date in a specified format
GENKEY()	Generates a unique key, 19 characters in length (RECORD section field input)
GENKEYCOL()	Generates a unique key, 19 characters in length (mapping section column input)
INSTR()	Determines the position of the first character of the first occurrence of one string within another
INSTRREV()	Determines the position of the last character of the last occurrence of one string within another
ISNULL()	Determines whether a column contains a null value
ISNUMERIC()	Determines whether a string is numeric
LCASE()	Converts a string to lowercase characters
LEFT()	Returns a specified number of characters from the left side of a string
LEN()	Returns the length of a string
LPAD()	Adds a specified character to the left side of a string to achieve a specified length
LTRIM()	Removes all instances of a specified character from the left side of a string
MID()	Returns a specified number of characters from a string
PAD()	Adds a specified character to both sides of a string to achieve a specified length
REPLACE()	Finds and replaces a substring within a string
RIGHT()	Returns a specified number of characters from the right side of a string
RPAD()	Adds a specified character to the right side of a string to achieve a specified length
RTRIM()	Removes all instances of a specified character from the right side of a string
SPACE()	Returns a string consisting of a specified number of spaces
STR()	Converts a numeric value into a string value
STRING()	Returns a string consisting of a specified character repeated a specified number of times
STRREV()	Reverses a string
TIME()	Returns the current time in a specified format
TRIM()	Removes all instances of a specified character from the left and right sides of a string
UCASE()	Converts a string to uppercase characters
VALF()	Converts a string containing numeric characters into a float value
VALI()	Converts a string containing numeric characters into an integer value




Math Functions

The following table lists in alphabetical order the math functions that can be used in NDL++ scripts, and provides a short description of each function along with its input and output data types. More detailed descriptions and examples are included in the NDL++ Math Functions Syntax and Examples section of the SAND CDBMS Tools Reference Guide.

Note:
When field values are to be considered as numeric values (float or integer type) by the NDL++ script interpreter, they must be declared as such in a TYPE section of the load specification script or in the appropriate portion of the RECORD section. Consult the SAND CDBMS Tools Reference Guide for more information.

Function	Description
ABS(x)	Calculates the absolute value of x
ATN(x)	Calculates the arctangent of x in radians
COS(x)	Calculates the cosine of x in radians
EXP(x)	Calculates the exponential of x
LOGN(x)	Calculates the natural logarithm of x
POW(x,y)	Calculates x raised to the power of y
ROUND(x)	Rounds x to the decimal point
SIGN(x)	Determines the sign of x: returns 1 if x is positive, �1 if x is negative, and 0 if x is zero.
SIN(x)	Calculates the sine of x in radians.
SQR(x)	Calculates the square root of x
TAN(x)	Calculates the tangent of x in radians
TRUNC(x)	Truncates x at the decimal point

Use the following links to go to more detailed information about NDL++ scripts:

• Detailed descriptions of NDL++ functions
• Variables
• NDL++ Conditional Expression Operators