RE: [sqlite] column def vs. constraint at end of create table stmt

[itIsMe]

>>You can see that the only way to create a two-column constraint is to
use 
>>this syntax (unless you want to define an index, that is).

>>Guy


hi -

I can see where I was confused now.
I will make the required changes.

thanks for your help,
jim

Re: [sqlite] column def vs. constraint at end of create table stmt

[Guy Hachlili]

At 18:57 11/2/2004 -0500, you wrote:
if I have a column def statement for every field and specify unique and
primary constraints in each column def, what is the reason the
constraint that goes on the very end of the create table would be needed
[, constraint]*  
 column-def ::= name [type] [[CONSTRAINT name] column-constraint]*
 sql-command ::= CREATE [TEMP | TEMPORARY] TABLE table-name (
column-def [, column-def]*
[, constraint]*
)
Some database users like to have constraints for more then one column at a 
time; for example, creating a unique constraint for two columns together. 
As constraint is defined thus:

constraint ::=  PRIMARY KEY ( column-list ) [ conflict-clause ] |
  UNIQUE ( column-list ) [ conflict-clause ] |
  CHECK ( expr ) [ conflict-clause ]
You can see that the only way to create a two-column constraint is to use 
this syntax (unless you want to define an index, that is).

Guy

[sqlite] column def vs. constraint at end of create table stmt

[j-marvin]

hi-

I am working on making my program for viewing sql statement results and
changing table structure a little nicer.  the reason the question came
about below is I thought I'd like to add capability to have more than
one field be the primary key and also would like to add the constraint
unique to work the same.

if I have a column def statement for every field and specify unique and
primary constraints in each column def, what is the reason the
constraint that goes on the very end of the create table would be needed
[, constraint]*  

 column-def ::= name [type] [[CONSTRAINT name] column-constraint]* 

 sql-command ::= CREATE [TEMP | TEMPORARY] TABLE table-name (
column-def [, column-def]*
[, constraint]*
) 

thank you very much,
jim