Type creation needing an extra slash in Sqlplus

Question

DB Version:10gR2
A table can be created with the termination charachter semicolon plus enter. But when creating TYPEs we need an extra forward slash.
Why is that?
SQL> create table xyz(col1 number(4));
Table created.
SQL> CREATE OR REPLACE TYPE UID_TYPES  AS TABLE OF UIDLIST;
  2  /                             ------------------------------> the slash i am talking about
Type created.

Answer 1

GarryB wrote:
A table can be created with the termination charachter semicolon plus enter. But when creating TYPEs we need an extra forward slash.
Why is that?The semicolon for a "+CREATE TYPE+" indicates the end of the type definition. Other SQL commands does not need that - as other commands do not mix PL code with SQL DDL commands.
Note that a type is defined as a SQL type, but can have PL methods, constructors and so on. This makes the "+CREATE TYPE+" SQL DDL command different from other DDLs - as it includes PL code syntax. For that reason the parser needs to know exactly where the type definition terminates. Thus the semi-colon.
Now for the confusing part. SQL*Plus needs to know when you have finished typing so that it can transmit the block of text that you typed to the Oracle server to be parsed and executed.
SQL*Plus uses 2 characters to allow you to tell it "+send this typed text to Oracle+" - it uses the semi-colon and the forward slash.
Thus the confusion - as SQL*Plus (client) now uses the very same delimiter that Oracle (server) uses. So SQL*Plus have some built-in parsing intelligence. It monitors what you type. If you type a plain vanilla SQL statement like this...
SQL> select empid from emp *;*
.. it realises that the *;* is the instruction for it to send the text "+select empid from emp+" to the server.
If you type a PL type instruction, SQL*Plus realises that you will be using semi-colons as command delimiters - and it will not send the text thus far typed to Oracle. Instead it will wait for you to tell it to send the text when you use the forward slash.
When you do a type definition, SQL*Plus knows that you need to use a semi-colon as end of statement character. So it will wait for you to finish typing and indicate that you're done type using a forward slash. E.g you type:
SQL> create or replace type TStrings as table of varchar2(4000);
+2> */*+
And SQL*Plus sends the text "+create or replace type TStrings as table of varchar2(4000);+" to Oracle for execution.
So be careful not to confuse SQL*Plus "transmit text" characters with SQL and PL/SQL command delimiters.. or the SQL*Plus primitive macro language with the formal procedural language of PL/SQL.