Re: Some basic SQL Questions

"Steven O." <Steven@OpZZREMOVE_ALL_Zs_AND_ALL_BETWEEN_ZZComm.com> wrote:
hh73001fej4r1hotrvk030ubmpffdc6r0a@4ax.com...
> First, this may not be the correct newsgroup.  I have some relatively
> basic questions on SQL.  I tried to find a newsgroup that was
> specifically just about SQL, and was surprised to find that all the
> SQL-related newsgroups seem to be product related.  But if I missed
> something, and someone can steer me to a correct newsgroup, please do
> so.
    comp.databases.theory covers database theory. You can find some stuff
on SQL standards. For the basic SQL, some textbooks on SQL is helpful.

>
> My specific questions:
>
> 1.  I want to put comments in an SQL script.  For example, I want
> something like
>
> CREATE TABLE myTable
> (field1 CHAR(10),  /* References the field1 table */
> field2 DECIMAL(3,2) /* References field2 table */
> );

    The standard way is using "--". Like,
        -- create a emp table
        create table emp(
            fno int,             -- number of emp
            fname char(8)  -- name of emp.
        )

    Some DBMSs, e.g. PostgreSQL, also support /* ... */.

>
> Here, I've used C-style comments, but I don't think that works with
> SQL.  Is there any other syntax for sticking comments in a script?
>
> 2.  I am writing my script based on some texts from an Oracle class I
> took a year ago.  But an online .pdf tutorial I found lists some data
> types that are not in my text:
> varchar2(n)
> number(o,d)
> Are these valid!?

    See ORACLE's manuals for details. They are valid data types
in ORACLE.

>
> 3.  Is there any kind of "memo" field in SQL?  My database references
> some text that may be arbitrary in length (like ingredients for a
> recipe), and a way to link to memo fields would be helpful.  Or, is
> that the purpose of the varchar2 data type?

    Use BYTEA/TEXT in PostgreSQL.
    Use BLOB/CLOB in standard SQL, ORACLE, ....
    Use IMAGE/TEXT in MSSQL.

>
> Thanks in advance for all replies.

    You are welcome.

>
> Steve O.
>
>
> Standard Antiflame Disclaimer:  Please don't flame me.  I may actually
*be* an idiot, but even idiots have feelings.