Conversion functions in BODS with Examples_2

[former_member190054]

                                            Conversion functions in BODS_Part2

In this section I will explain mainly three conversion function in BO data service. They are mainly CAST, To_Date and load_to_XML.

1. CAST

Cast function used to explicitly convert an expression in one data type to another data type. The syntax for this function is given below.

CAST(Expression, data type) return data type.

The expression is the input which will be convert to target data type and the data type should be in build data type .

Syntax for different data type is given below .Please see below given table.

Data Type	Syntax
Varchar	Cast(expression,’ varchar(length)’)
decimal	Cast(expression,’decimal(Precision,scale)’)
Integer	Cast(expression,’int’)
Real	Cast(expression,’real’)
Double	Cast(expression,’double’)
Timestamp	Cast(expression,’timestamp’)
Datetime	Cast(expression,’datetime’)
Date	Cast(expression,’date’)
Time	Cast(expression,’time’)
Intervel	Cast(expression,’intervel’)

Examples for those functions are given below.

Input Expression	Source and target Datatype	Ouput
CAST(‘12.20’,’INT’)	Varchar to int	12
CAST(‘12.20’,’DECIMAL(3,1)’)	Varchar to decimal	12.12
CAST(12.20,’REAL’)	Decimal to real	12.200000
CAST(12.20,’DOUBLE’)	Decimel to double	12.200000
CAST(12.20,’VARCHAR(4)’)	Decimel to varchar	12.20
Cast(‘2012.01.01’,’date’)	Varchar to date	2012.01.01
Cast(‘2012.01.01’,’datetime’)	Varchar to datetime	2012.01.01 00:00:00
Cast(‘2012.01.01 12:01:12’,’timestamp’)	Datetime to timestamp	2012.01.01 12.01.12.000000000
Cast(‘sysdate(),’time’)	Datetime to time	12:21:00
Cast(12.121239,’intervel’)	Integer  to interval	12.121239

This table shows all the data type conversion valid for the cast functions.

From-To	Varchar	Date	DateTime	Integer	Real	Double	Interval	Timestamp	Time	Decimal
Varchar	x	x	x	x	x	x	x	x	x	x
Date	x	x	x					x
DateTime	x	x	x					x	x
Integer	x			x	x	x	x			x
Real	x			x	x	x	x			x
Double	x			x	x	x	x			x
Decimal	x			x	x	x	x			x
Interval	x			x	x	x	x			x
Timestamp	x	x	x					x	x
Time	x			x	x	x	x			x

From above table you will get which one data type can be convert to another one and which all are can’t convert to other data type.

2. TO_DATE

The to_date function used to convert a string to date value. This function converts a string into date format.

The string can also convert into datetime and time value format.

If the input string has more characters than the format string, the extra characters in the input string will be ignored and will be initialized to the default value.

For example, to_date('10.02.2007 10:12:12, 'DD.MM.YYYY') will convert the date to 10.02.2007 00.00.00. The time part in the input string will be ignored and initialized to 0.

The syntax of the function is given below.

To_date(string,format) returns date ,datetime or time

FORMATS
DD	Day of the Month(2 Digit)
MM	Month Number(2 Digit)
MONTH	Full Month Name
MON	Month name(3 char)
YY	Year(2 Digit)
YYYY	Year(4 Digit)
HH24	Hour(2 Digit)
MI	Minutes(2 Digit)
SS	Seconds(2 Digit)
FF	Sub Seconds(Upto 9 Digit)

The examples for this function are given below. A string can be converted into date value based on the above given format.

Please refer below examples.

Function	Result
To_date(‘jun 18,2012’,’MON DD,YYYY’)	2012.06.18 00:00:00
To_date(‘1March1900’,’DDMONTHYYYY’)	1900.03.01 00:00:00
To_date(’12-12-01 13:12’,’MM-YY-DD HH24:MM’)	2012.12.01 12:00
To_date(‘2012Jan01’,’YYYYMONDD’)	2012.01.01 00:00:00

These are examples for the string to date conversion .you can do any conversion from string to date based on the format given.

3. LOAD_TO_XML

This function convert an NRDT(Nested Relational Data Model) into XML and place it as a single column during the data load.

If the function fails during XML conversion then data services will return NULL value.

The Syntax for this is:

Load_to_XML(nested_table name,Schema_dtd_name,enable_validation,xml_header,replace_string_nulls,is_top_level_element,max size)

default is UTF-8

nested_table_name	Name of NRDM table.
Schema_dtd_name	Name of DTD or XML Schema
enable_validation	Enter 1 to validate and 0 disable validation
xml_header
replace_string_nulls	Replace null with this value
is_top_level_element	1 or 0
max size	Expected size of the XML.

Regards

Asgar