Basics related to Macros in Teradata.
A Macro: It is a collection of SQL queries preferably DML statments and it is stored as an object in DD(Data Dictionary). Unlike VIEWS (we will deal about Views in another post), a macro can have multiple sequels. It is known that a macro can handle many DML and it is restricted to only one DDL.
Reason: DDL statements like Create,Alter,Drop,Rename generally locks the DD for their processing, since macros transaction is an internal process it is highly dependent on DD. Therefore DDL can be last statement in a macro. - This is what provided as theoretical explanation .
Example:
CM AS // CM doesnt work with Queryman better try with BTEQ
or
CREATE MACRO MyMacroName AS
(
insert into (eno,name,ereqno) emp values (101,'Rajesh',43243259);
select * from emp;
//DDL stmt here (doesnt work with queryman)
)
Issue: There is an issue with macro that, DDL couldnt be even as last statement in a macro(with Queryman). I used Teradata 12 and I am getting Warning as Data Dictionary must be solitary. I will update after working with BTEQ.
Parameterized Macro:
//paramNum is passed as Parameter to Select statement.
//passed parameter shd be accessed using =:paramname
CREATE MACRO macro_name (paramNum integer) AS
{
DMLs here....
select ename,esal from emp where eno = :paramName ;
};
REPLACE Macro:
If you require more DMLs to be added to an existing macro, you can use
REPLACE MACRO AS
{[insert];
[update];
[delete];
[select];);
To Execute Macro:
EXEC []
eg: exec myfirsmacro_name;
exec myfirsmacro_name (invalue=1,invalue='abc');
To Drop:
DROP MACRO macro-name;
NOTE: TERADATA sql is case-blind and so no need to worry about capitalization,etc
Comments highly appreciated.
or
CREATE MACRO MyMacroName AS
(
insert into (eno,name,ereqno) emp values (101,'Rajesh',43243259);
select * from emp;
//DDL stmt here (doesnt work with queryman)
)
Issue: There is an issue with macro that, DDL couldnt be even as last statement in a macro(with Queryman). I used Teradata 12 and I am getting Warning as Data Dictionary must be solitary. I will update after working with BTEQ.
Parameterized Macro:
//paramNum is passed as Parameter to Select statement.
//passed parameter shd be accessed using =:paramname
CREATE MACRO macro_name (paramNum integer) AS
{
DMLs here....
select ename,esal from emp where eno = :paramName ;
};
REPLACE Macro:
If you require more DMLs to be added to an existing macro, you can use
REPLACE MACRO
{[insert];
[update];
[delete];
[select];);
To Execute Macro:
EXEC
eg: exec myfirsmacro_name;
exec myfirsmacro_name (invalue=1,invalue='abc');
To Drop:
DROP MACRO macro-name;
NOTE: TERADATA sql is case-blind and so no need to worry about capitalization,etc
Comments highly appreciated.
