Ascential DataStage Parallel Modify Stage Programming GuideFrom MIKE2.0 Methodology

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Contents

[hide] 1 Keeping and Dropping Fields 2 Renaming Fields

3 Duplicating a Field and Giving It a New Name

4 Changing a Field’s Data Type

5 Data Type Conversion Errors

6 Date Field Conversions

7 Decimal Field Conversions

8 Raw Field Length Extraction

9 string and ustring Conversions

10 String Conversions and Lookup Tables

11 time Type Conversions Provided by modify

12 The modify Operator and Nulls

13 Related Content

Keeping and Dropping Fields

Invoke the modify operator to keep fields in or drop fields from the output. Here are the effects of keeping and dropping fields:

If you choose to drop a field or fields, all fields are retained except those you explicitly drop.

If you chose to keep a field or fields, all fields are excluded except those you explicitly keep.

In osh you specify either the keyword keep or the keyword drop to keep or drop a field, as follows: modify 'keep field1, field2, ... fieldn; ' modify 'drop field1, field2, ... fieldn;'

Renaming Fields

To rename a field specify the attribution operator (=) , as follows: modify ' newField1=oldField1; newField2=oldField2;...newFieldn=oldFieldn; '

Duplicating a Field and Giving It a New Name

You can duplicate a field and give it a new name, that is, create multiple new names for the same old name. You can also convert the data type of a field and give it a new name. To duplicate and rename a field or duplicate it and change its data type use the attribution operator (=) . The operation must be performed by one modify operator, that is, the renaming and duplication must be specified in the same command as follows: a_1 = a

Changing a Field’s Data Type

Sometimes, although field names are the same, an input field is of a type that differs from that of the same field in the output, and conversion must be performed. Orchestrate often automatically changes the type of the source field to match that of the destination field. Sometimes, however, you must invoke the modify operator to perform explicit conversion. The next sections discuss default data type conversion and data type conversion errors. The subsequent sections discuss non-default conversions of Orchestrate data types.

Data Type Conversion Errors

A data type conversion error occurs when a conversion cannot be performed. Orchestrate’s action when it detects such an error differs according to whether the time timestamp destination field has been defined as nullable, according to the following three rules:

If the destination field has been defined as nullable, Orchestrate sets it to null. If the destination field has not been defined as nullable but you have directed modify to

convert a null to a value, Orchestrate sets the destination field to the value. To convert a null to a value supply the handle_null conversion specification.

For complete information on converting a null to a value.

If the destination field has not been defined as nullable, Orchestrate issues an error message and terminates the application. However, a warning is issued at step-check time. To disable the warning specify the nowarn option.

Date Field Conversions

dateField = date_from_days_since[date](int32Field)

date from days since Converts an integer field into a date by adding the integer to the specified base date. The date must be in the format yyyy-mm-dd.

dateField = date_from_julian_day(uint32Field)

date from Julian day

dateField = date_from_string

[date_format | date_uformat] (stringField)

dateField = date_from_ustring

[date_format |date_uformat] (ustringField) date from string or ustring Converts the string or ustring field to a date representation using the specified date_format. By default, the string format is yyyy-mm-dd.

dateField = date_from_timestamp(tsField)

date from timestamp Converts the timestamp to a date representation.

int8Field = month_day_from_date(dateField)

day of month from date

int8Field = weekday_from_date[originDay](dateField)

day of week from date originDay is a string specifying the day considered to be day zero of the week. You can specify the day using either the first three characters of the day name or the full day name. If omitted, Sunday is defined as day zero. The originDay can be either single- or double-quoted or the quotes can be omitted.

int16Field = year_day_from_date(dateField)

day of year from date (returned value 1–366)

int32Field = days_since_from_date[source_date]

(dateField) days since date Returns a value corresponding to the number of days from source_date to the contents of dateField. source_date must be in the form yyyy-mm-dd and can be quoted or unquoted.

uint32Field = julian_day_from_date(dateField)

Julian day from date

int8Field = month_from_date(dateField) month from date dateField = next_weekday_from_date[day](dateField)

next weekday from date The destination contains the date of the specified day of the week soonest after the source date (including the source date). day is a string specifying a day of the week. You can specify day by either the first three characters of the day name or the full day name. The day can be quoted in either single or double quotes or quotes can be omitted.

dateField = previous_weekday_from_date[day]

(dateField) previous weekday from date The destination contains the closest date for the specified day of the week earlier than the source date (including the source date) The day is a string specifying a day of the week. You can specify day using either the first three characters of the day name or the full day name. The day can be either single- or double- quoted or the quotes can be omitted.

stringField = string_from_date [date_format | ufornat] (dateField) ustringField = ustring_from_date [date_format | date_uformat] (dateField) strings and

ustrings from date

Converts the date to a string or ustring representation using the specified date_format. By default, the string format is yyyy-mm-dd.

tsField = timestamp_from_date[time](dateField) timestamp from date

The time argument optionally specifies the time to be used in building the timestamp result and must be in the form hh:nn:ss. If omitted, the time defaults to midnight.

int16Field = year_from_date(dateField) year from date int8Field=year_week_from_date(dateField) week of year from date

Decimal Field Conversions

By default Orchestrate converts decimal fields to and from all numeric data types and to and from string fields. The default rounding method of these conversion is truncate toward zero. However, the modify operator can specify a different rounding method.

The operator can specify fix_zero so that a source decimal containing all zeros (by default illegal) is treated as a valid decimal with a value of zero. Orchestrate does not perform range or representation checks of the fields when a source and destination decimal have the same precision and scale. However, you can specify the decimal_from_decimal conversion to force Orchestrate to perform an explicit range and representation check. This conversion is useful when one decimal supports a representation of zeros in all its digits (normally illegal) and the other does not. The following table list the conversions involving decimal fields: A decimal

conversion to or from a numeric field can be specified with any Orchestrate numeric data type. Orchestrate performs the necessary modification. For example, int32_from_decimal converts a decimal either to an int32 or to any numeric data type, such as int16, or uint32. The fix_zero specification causes a decimal field containing all zeros (normally illegal) to be treated as a valid zero. Omitting fix_zero causes Orchestrate to issue a conversion error when it encounters a decimal field containing all zeros.

decimal from decimal decimalField = decimal_from_decimal[r_type](decimalField) decimal from dfloat decimalField = decimal_from_dfloat[r_type](dfloatField)

decimal from string decimalField = decimal_from_string[r_type](stringField)

decimal from ustring decimalField = decimal_from_ustring[r_type](ustringField)

dfloat from decimal dfloatField = dfloat_from_decimal[fix_zero](decimalField)

dfloat from decimal dfloatField = mantissa_from_decimal(decimalField)

dfloat from dfloat dfloatField = mantissa_from_dfloat(dfloatField)

int32 from decimal int32Field = int32_from_decimal[r_type, fix_zero](decimalField)

int64 from decimal int64Field = int64_from_decimal[r_type, fix_zero](decimalField)

string from decimal stringField = string_from_decimal[fix_zero][suppress_zero](decimalField)

ustring from decimal ustringField = ustring_from_decimal[fix_zero][suppress_zero](decimalField)

uint64 from decimal uint64Field = uint64_from_decimal[r_type, fix_zero](decimalField)

The suppress_zero argument specifies that the returned string value will have no leading or trailing zeros. Examples: 000.100 -> 0.1; 001.000 -> 1; -001.100 -> -1.1 Rounding Type You can optionally specify a value for the rounding type (r_type) of many conversions. The values of r_type are:

ceil: Round the source field toward positive infinity. This mode corresponds

to the IEEE 754 Round Up mode. Examples: 1.4 -> 2, -1.6 -> -1

floor: Round the source field toward negative infinity. This mode corresponds

to the IEEE 754 Round Down mode. Examples: 1.6 -> 1, -1.4 -> -2

round_inf: Round or truncate the source field toward the nearest representable value, breaking ties by rounding positive values toward positive infinity and negative values toward negative infinity. This mode corresponds to the COBOL ROUNDED mode.

Examples: 1.4 -> 1, 1.5 -> 2, -1.4 -> -1, -1.5 -> -2

trunc_zero (default): Discard any fractional digits to the right of the rightmost fractional digit supported in the destination, regardless of sign. For example, if the destination is an integer, all fractional digits are truncated. If the destination is another decimal with a smaller scale, round or truncate to the scale size of the destination decimal. This mode corresponds to the COBOL INTEGER-PART function.

Examples: 1.6 -> 1, -1.6 -> -1 Figure 19 shows the conversion of a decimal field to a 32-bit integer with a rounding mode of ceil rather than the default mode of truncate to zero:

The osh syntax for this conversion is: 'field1 = int32_from_decimal[ceil,fix_zero] (dField);' where fix_zero ensures that a source decimal containing all zeros is treated as a valid representation.

Raw Field Length Extraction

Invoke the modify operator and the raw_length option to extract the length of a raw field. This specification returns an int32 containing the length of the raw field and optionally passes through the source field. Table 32 raw Field Functions Conversion Specification Description

rawField = raw_from_string(string) Returns string in raw representation. rawField = u_raw_from_string(ustring) Returns ustring in raw representation.

int32Field = raw_length(raw) Returns the length of the raw field.

Use the modify operator to perform the following modifications involving string and ustring fields: Extract the length of a string. Convert long strings to shorter strings by string extraction. Convert strings to and from numeric values using lookup tables .

string and ustring Conversions

( stringField=string_trim [character, direction, justify] (string) You can use this function to remove the characters used to pad variable-length strings when they are converted to fixed-length strings of greater length. By default, these characters are retained when the fixed-length string is then converted back to a variable-length string. The character argument is the character to remove. It defaults to NULL. The value of the direction and justify arguments can be either begin or end; direction defaults to end, and justify defaults to begin. justify has no affect when the target string has variable length. Examples:

name:string = string_trim[NULL, begin](name)

removes all leading ASCII NULL characters from the beginning of name and places the remaining characters in an output variable-length string with the same name.

hue:string[10] = string_trim['Z', end, begin](color)

removes all trailing Z characters from color, and left justifies the resulting hue fixed-length string.

stringField=substring(string, starting_position, length) ustringField=u_substring(ustring, starting_position, length)

Copies parts of strings and ustrings to shorter strings by string extraction. The starting_position specifies the starting location of the substring; length specifies the substring length. The arguments starting_position and length are uint16 types and must be positive (>= 0).

stringField=lookup_string_from_int16 [tableDefinition](int16Field) ustringField=lookup_ustring_from_int16 [tableDefinition](int16Field)

Converts numeric values to strings and ustrings by means of a lookup table.

int16Field=lookup_int16_from_string [tableDefinition](stringField) int16Field=lookup_int16_from_ustring [tableDefinition](ustringField)

Converts strings and ustrings to numeric values by means of a lookup table.

uint32 = lookup_uint32_from_string [tableDefinition](stringField) uint32 =lookup_uint32_from_ustring [tableDefinition](ustringField)

stringField=lookup_string_from_uint32 [tableDefinition](uint32Field)

ustringField=lookup_ustring_from_uint32 [tableDefinition](uint32Field)

Converts numeric values to strings and ustrings by means of a lookup table.

stringField = string_from_ustring(ustring) Converts ustrings to strings. ustringField = ustring_from_string(string) Converts strings to ustrings.

decimalField = decimal_from_string(stringField) Converts strings to decimals.

decimalField = decimal_from_ustring(ustringField) Converts ustrings to decimals.

stringField = string_from_decimal[fix_zero] [suppress_zero] (decimalField) Converts decimals to strings.

fix_zero causes a decimal field containing all zeros to be treated as a valid zero. suppress_zero specifies that the returned ustring value will have no leading or trailing zeros.

ustringField = ustring_from_decimal[fix_zero] [suppress_zero] (decimalField) Converts decimals to ustrings.

See string_from_decimal above for a description of the fix_zero and suppress_zero arguments.

dateField = date_from_string [date_format | date_uformat] (stringField)

dateField = date_from_ustring [date_format | date_uformat] (ustringField) date from string or ustring

Converts the string or ustring field to a date representation using the specified date_format or date_uformat. By default, the string format is yyyy-mm-dd.

stringField = string_from_date [date_format | date_uformat] (dateField) ustringField = ustring_from_date [date_format | date_uformat] (dateField) strings and

ustrings from date

Converts the date to a string or ustring representation using the specified date_format or date_uformat. By default, the string format is yyyy-mm-dd.

int32Field=string_length(stringField) int32Field=ustring_length(ustringField)

Returns an int32 containing the length of a string or ustring.

stringField=substring [startPosition,len] (stringField) ustringField=substring [startPosition,len] (ustringField) Converts long strings/ustrings to

shorter strings/ustrings by string extraction. The startPosition specifies the starting location of the substring; len specifies the substring length. If startPosition is positive, it specifies the byte offset into the string from the beginning of the string. If startPosition is negative, it specifies the byte offset from the end of the string.

stringField=uppercase_string (stringField)

ustringField=uppercase_ustring (ustringField) Convert strings and ustrings to all upper case.

Non-alphabetic characters are ignored in the conversion.

stringField=lowercase_string (stringField) ustringField=lowercase_ustring (ustringField)

Convert stringsand ustrings to all lower case. Non-alphabetic characters are ignored in the conversion.

stringField = string_from_time [time_format | time_uformat ] (timeField) ustringField = ustring_from_time [time_format | time_uformat] (timeField) string and

ustring from time

Converts the time to a string or ustring representation using the specified time_format or time_uformat. The time_format options are described below.

The following osh command converts a string field to lowercase: osh “... | modify “lname=lowercase_string(lname)�? | peek�?

stringField = string_from_timestamp [timestamp_format | timestamp_uformat] (tsField) ustringField = ustring_from_timestamp [timestamp_format | timestamp_uformat]

(tsField) strings and ustrings from timestamp

Converts the timestamp to a string or ustring representation using the specified timestamp_format or timestamp_uformat. By default, the string format is %yyyy-%mm-%dd hh:mm:ss.

tsField = timestamp_from_string [timestamp_format | timestamp_uformat] (stringField) tsField = timestamp_from_ustring [timestamp_format | timestamp_uformat] (usringField)

timestamp from strings and ustrings

Converts the string or ustring to a timestamp representation using the specified timestamp_format or timestamp_uformat. By default, the string format is yyyy-mm-dd hh:mm:ss.

timeField = time_from_string [time_format | time_uformat](stringField) timeField = time_from_ustring [time_format | time_uformat] (ustringField) string and

ustring from time

Converts the time to a string or ustring representation using the specified time_format.

String Conversions and Lookup Tables

You can construct a string lookup table to use when default conversions do not yield satisfactory results. A string lookup table is a table of two columns and as many rows as are required to perform a conversion to or from a string. Each row of the lookup table specifies an association between a 16-bit integer or unsigned 32-bit integer value and a string or ustring. Orchestrate scans the Numeric Value or the String or Ustring column until it encounters the value or string to be translated. The output is the corresponding entry in the row. The numeric value to be converted may be of the int16 or the uint32 data type. Orchestrate converts strings to values of the int16 or uint32 data type using the same table. If the input contains a numeric value or string that is not listed in the table, Orchestrate operates as follows:

If a numeric value is unknown, an empty string is returned by default. However, you can set a default string value to be returned by the string lookup table.

If a string has no corresponding value, 0 is returned by default. However, you can set a default numeric value to be returned by the string lookup table.

Here are the options and arguments passed to the modify operator to create a lookup table:

intField = lookup_int16_from_string[tableDefinition](source_stringField); | intField = lookup_int16_from_ustring[tableDefinition](source_ustringField);

OR:

intField = lookup_uint32_from_string[tableDefinition](source_stringField); | intField = lookup_uint32_from_ustring[tableDefinition](source_ustringField);

Numeric Value String or Ustring numVal1 string1 | ustring1 numVal2 string2 | ustring1 ... ... numVal3 stringn | ustringn

stringField = lookup_string_from_int16[tableDefinition](source_intField); | ustringField = lookup_ustring_from_int16[tableDefinition](source_intField);

OR:

stringField = lookup_string_from_uint32[tableDefinition](source_intField); ustringField = lookup_ustring_from_uint32[tableDefinition](source_intField);

where: tableDefinition defines the rows of a string or ustring lookup table and has the following form: {propertyList} ('string' | 'ustring' = value; 'string' | 'ustring'= value; ... ) where:

propertyList is one or more of the following options; the entire list is enclosed in braces and properties are separated by commas if there are more than one:

case_sensitive: perform a case-sensitive search for matching strings; the default is case-insensitive.

default_value = defVal: the default numeric value returned for a string that does not match any of the strings in the table.

default_string = defString: the default string returned for numeric values that do not match any numeric value in the table.

string or ustring specifies a comma-separated list of strings or ustrings associated with value; enclose each string or ustring in quotes.

value specifies a comma-separated list of 16-bit integer values associated with string or ustring.

The following osh code performs the conversion: modify ’gender = lookup_int16_from_string[{default_value = 2} ('f' = 0; 'female' = 0; 'm' = 1; 'male' = 1;)] (gender);' In this example, gender is the name of both the source and the destination fields of the translation. In addition, the string lookup table defines a default value of 2; if gender contains a string that is not one of "f", "female", "m", or "male", the lookup table returns a value of 2.

Orchestrate performs no automatic conversions to or from the time data type. You must invoke the modify operator if you want to convert a source or destination time field. Most time field conversions extract a portion of the time, such as hours or minutes, and write it into a destination field.

time Type Conversions Provided by modify

Time conversion to a numeric field can be used with any Orchestrate numeric data type. Orchestrate performs the necessary modifications to translate a conversion result to the numeric data type of the destination. For example, you can use the conversion hours_from_time to convert a time to an int8, or to an int16, int32, dfloat, and so on.

By default Orchestrate converts a source timestamp field only to either a time or date destination field. However, you can invoke the modify operator to perform other conversions.

Timestamp conversion of a numeric field can be used with any Orchestrate numeric data type. Orchestrate performs the necessary conversions to translate a conversion result to the numeric data type of the destination. For example, you can use the conversion timet_from_timestamp to convert a timestamp to an int32, dfloat, and so on.

int8Field = hours_from_time(timeField) hours from time int32Field = microseconds_from_time(timeField) microseconds from time

int8Field = minutes_from_time(timeField) minutes from time

dfloatField = seconds_from_time(timeField) seconds from time

dfloatField = midnight_seconds_from_time(timeField) seconds-from-midnight from time

stringField = string_from_time [time_format | time_uformat] (timeField)

ustringField = ustring_from_time [time_format |time_uformat] (timeField) string and ustring from time

Converts the time to a string or ustring representation using the specified time_format or time_uformat.

timeField = time_from_midnight_seconds(dfloatField) time from seconds-from-midnight timeField = time_from_string [time_format | time_uformat ](stringField)

timeField = time_from_ustring [time_format | time_uformat] (ustringField) time from string

Converts the string or ustring to a time representation using the specified time_format or time_uformat.

timeField = time_from_timestamp(tsField) time from timestamp tsField = timestamp_from_time [date](timeField) timestamp from time

The date argument is required. It specifies the date portion of the timestamp and must be in the form yyyy-mm-dd.

dfloatField = seconds_since_from_timestamp [timestamp](tsField) seconds_since from timestamp

tsField= timestamp_from_seconds_since [timestamp](dfloatField) timestamp from seconds_since

stringField = string_from_timestamp [timestamp_format | timestamp_uformat] (tsField)

ustringField = ustring_from_timestamp [timestamp_format | timestamp_uformat] (tsField) strings and ustrings from timestamp

Converts the timestamp to a string or ustring representation using the specified timestamp_format or timestamp_uformat. By default, the string format is %yyyy-%mm-%dd hh:mm:ss.

int32Field = timet_from_timestamp (tsField) time_t from timestamp

int32Field contains a timestamp as defined by the UNIX time_t representation.

dateField = date_from_timestamp(tsField) date from timestamp

Converts the timestamp to a date representation.

tsField = timestamp_from_string [timestamp_format | timestamp_uformat] (stringField) tsField = timestamp_from_ustring [timestamp_format | timestamp_uformat] (usringField)

timestamp from strings and ustrings

Converts the string or ustring to a timestamp representation using the specified timestamp_format. By default, the string format is yyyy-mm-dd hh:mm:ss.

tsField = timestamp_from_timet (int32Field) timestamp from time_t

int32Field must contain a timestamp as defined by the UNIX time_t representation.

tsField = timestamp_from_date [time](dateField) timestamp from date

The time argument optionally specifies the time to be used in building the timestamp result and must be in the form hh:mm:ss. If omitted, the time defaults to midnight.

tsField = timestamp_from_time [date](timeField) timestamp from time

The date argument is required. It specifies the date portion of the timestamp and must be in the form yyyy-mm-dd.

tsField = timestamp_from_date_time (date, time)

Returns a timestamp from date and time. The date specifies the date portion (yyyy-nn-dd) of the timestamp. The time argument specifies the time to be used when building the timestamp. The time argument must be in the hh:nn:ss format.

timeField = time_from_timestamp(tsField) time from timestamp

The modify Operator and Nulls

All Orchestrate data types support nulls. As part of processing a record, an operator can detect a null and take the appropriate action, for example, it can omit the null field from a calculation or signal an error condition. Orchestrate represents nulls in two ways.

It allocates a single bit to mark a field as null. This type of representation is called an out-of-band null.

It designates a specific field value to indicate a null, for example a numeric field’s most negative possible value. This type of representation is called an inband null. In-band null representation can be disadvantageous because you must reserve a field value for nulls and this value cannot be treated as valid data elsewhere.

The modify operator can change a null representation from an out-of-band null to an in-band null and from an in-band null to an out-of-band null. The record schema of an operator’s input or output data set can contain fields defined to support out-of-band nulls. In addition, fields of an operator’s interface may also be defined to support out-of-band nulls. The next table lists the rules for handling nullable fields when an operator takes a data set as input or writes to a data set as output.

not_nullable not_nullable Source value propagates to destination. not_nullable nullable Source value propagates; destination value is never null.

nullable not_nullable If the source value is not null, the source value

propagates. If the source value is null, a fatal error occurs, unless you apply the modify operator, as in Out-of-Band to Normal Representation The modify operator can change a field’s null representation from a single bit to a value you choose, that is, from an out-of-band to an in-band representation. Use this feature to prevent fatal data type conversion errors that occur when a destination field has not been defined as supporting nulls. To change a field’s null representation from a single bit to a value you choose, use the following osh syntax:

destField[:dataType] = handle_null (sourceField,value)

where:

destField is the destination field’s name. dataType is its optional data type; use it if you are also converting types.

sourceField is the source field’s name

value is the value you wish to represent a null in the output. The destField is converted from an Orchestrate out-of-band null to a value of the field’s data type. For a numeric field value can be a numeric value, for decimal, string, time, date, and timestamp fields, value can be a string.

While in the input fields a null takes Orchestrate’s out-of-band representation, in the output a null in aField is represented by -128 and a null in bField is represented by ASCII XXXX (0x59 in all bytes). To make the output aField contain a value of -128 whenever the input contains an out-of-band null, and the output bField contain a value of 'XXXX' whenever the input contains an out-of-band null, use the following osh code: $ modifySpec = "aField = handle_null(aField, -128); bField = handle_null(bField, 'XXXX'); " $ osh " ... | modify '$modifySpec' | ... " Notice that a shell variable (modifySpec) has been defined containing the specifications passed to the operator. Normal to Out-of-Band Representation The modify operator can change a field’s null representation from a normal field value to a single bit, that is, from an in-band to an out-of-band representation. To change a field’s null representation to out-of band use the following osh syntax: destField[:dataType] = make_null(sourceField,value); Where:

destField is the destination field’s name. dataType is its optional data type; use it if you are also converting types.

sourceField is the source field’s name.

value is the value of the source field when it is null.

A conversion result of value is converted from an Orchestrate out-of-band null to a value of the field’s data type. For a numeric field value can be a numeric value, for decimal, string, time, date, and timestamp fields, value can be a string. The following osh syntax causes the aField of the output data set to be set to Orchestrate’s single-bit null representation if the corresponding input field contains -128 (in-band-null), and the bField of the output to be set to Orchestrate’s single-bit null representation if the corresponding input field contains 'XXXX' (inband-null). $modifySpec = "aField = make_null(aField, -128); bField = make_null(bField, 'XXXX'); " $ osh " ... | modify '$modifySpec' | ... " Notice that a shell variable (modifySpec) has been defined containing the specifications passed to the operator. Orchestrate supplies two other conversions to use with nullable fields, called null and notnull.

The null conversion sets the destination field to 1 if the source field is null and to 0 otherwise.

The notnull conversion sets the destination field to 1 if the source field is not null and to 0 if it is null.

In osh, define a null or notnull conversion as follows:

destField[:dataType] = null(sourceField); destField[:dataType] = notnull(sourceField);

By default, the data type of the destination field is int8. Specify a different destination data type to override this default. Orchestrate issues a warning if the source field is not nullable or the destination field is nullable.