Named parameters for SQL insert statement.

Db2 for i has in few occasions been a forerunner for features of SQL. So perhaps this idea could also be one of these features.

We have used named parameters for UDTF and stored procedures for quite some time.

SELECT *

FROM TABLE (QSYS2.IFS_OBJECT_STATISTICS(

START_PATH_NAME => '/usr',

SUBTREE_DIRECTORIES => 'NO'

) );

This idea will implement the same syntax for the SQL insert statements.

Particularly useful in combination with complex insert statements.

Example

CREATE TABLE TEST (MYNUMBER INT , MYNAME VARCHAR(256));

Here is the classical insert statement:

INSERT INTO TEST (MYNUMBER , MYNAME) VALUES(1, ‘JOHN’);

With this new idea, we could rewrite the statement to look like this:

INSERT INTO TEST (

MYNUMBER => 1 ,

MYNAME =>’JOHN’

);

At a first glance, it looks like syntactic sugar however the benefit is more obvious for more complex insert statements like this:

INSERT INTO TEST (

MYNUMBER => (SELECT COUNT(*) FROM SERVICES_INFO),

MYNAME => (SELECT MAX(NAME) FROM SERVICES_INFO)

);

Or even more clear when inserting multiple rows where default values are required:

INSERT INTO TEST

( MYNUMBER => (SELECT COUNT(*) FROM SERVICES_INFO)),

( MYNAME => (SELECT MAX(NAME) FROM SERVICES_INFO));

The above example would insert two rows where the first row will contain the result of an SQL query in MYNUMBER and leaving MYNAME the default value.

The next row would leave the MYNUMBER a default value, and MYNAME will contain the result of SQL query (or value or function call)

Perhaps the best feature of this new idea will be when you have a large number of columns to insert in one single statement. The readability of the insert statement would be much easier. It will be more obvious which data goes into which column that today can be quite painful.

INSERT INTO TABLE_WITH_LOADS_OF_COLUMNS (A,B,C,D,E,F,G,H,I)

VALUES ( 1, 2, 3, 4, 5, 6, 7, 8) ;

Did you spot the error? Here we are designating nine columns from A to I however only inserting eight values. It can be painful to spot these kind of errors.

Let's rewrite this statement that gives us no opportunity to make mistakes:

INSERT INTO TABLE_WITH_LOADS_OF_COLUMNS

VALUES ( A=>1, B=>2, C=> 3,D=> 4,E=> 5, F=>6, G=>7 , H=>8 ) ;

This feature should of course, also support parameter marker and host variables:

INSERT INTO TEST (

MYNUMBER => :MYNUMBER,

MYNAME => :MYNAME

);