dynamic plsql procedure has some issues while executing it? [duplicate] - stored-procedures

Question

Thanks for all,We can create a table dynamically with the help of execute immediate query. But when we create a table it is been created but if i wanted to create table dynamically with dynamic no of columns then question was raised. Actually I had created a table but when I created no of columns along with the table then a lots of errors raised. The following is the code which I had written in the Oracle in a procedure.
declare
no_of_cols number:=&no_of_cols;
colname varchar2(20);
coldata varchar2(20);
i number;
begin
execute immediate 'create table smap1(nam varchar2(10))';
age:='age';
datf:='number'
if(no_of_cols>=2) then
for i in 2..no_of_cols loop
colname:=age;
coldata:=datf;
execute immediate 'alter table smapl add '||colname||' '||coldata;
end loop;
end if;
end;
then this code executing with four columns with same type if no_of_cols is 5.Then i had modified the code and run the plsql program.the program is as follows
declare
no_of_cols number:=&no_of_cols;
colname varchar2(20);
age varchar2(20);
datf varchar2(20);
coldata varchar2(20);
i number;
begin
execute immediate 'create table smap1(nam varchar2(10))';
if(no_of_cols>=2) then
for i in 2..no_of_cols loop
age :=&age;
datf:=&datf;
colname:=age;
coldata:=datf;
execute immediate 'alter table smapl add '||colname||' '||coldata;
end loop;
end if;
end;
The following are the errors which are generated when the above procedure is created
[Error] Execution (13: 19): ORA-06550: line 13, column 19:
PLS-00103: Encountered the symbol ";" when expecting one of the following:
( - + case mod new not null <an identifier>
<a double-quoted delimited-identifier> <a bind variable>
continue avg count current exists max min prior sql stddev
sum variance execute forall merge time timestamp interval
date <a string literal with character set specification>
<a number> <a single-quoted SQL string> pipe
<an alternatively-quoted string literal with character set specification>
<an alternatively
i had done some modifications for the above plsql,then the plsql code will as follows
declare
no_of_cols number:=&no_of_cols;
colname varchar2(20):='&colname';
coldata varchar2(20):='&coldata';
i number;
begin
execute immediate 'create table smap1(nam varchar2(10))';
if(no_of_cols>=2) then
for i in 2..no_of_cols loop
execute immediate 'alter table smapl add '||colname||' '||coldata;
end loop;
end if;
end;
then after executing i am getting the following error and it doenot read column name dynamically
[Error] Execution (1: 1): ORA-02263: need to specify the datatype for this column
ORA-06512: at line 10

Answer 1

You cannot use semicolons in EXECUTE IMMEDIATE for single statements
Here's a quote from the documentation:
Except for multi-row queries, the dynamic string can contain any SQL statement (without the final semicolon) or any PL/SQL block (with the final semicolon).
Remove the semicolon from EXECUTE IMMEDIATE.
execute immediate 'create table smap1(nam varchar2(10));'; -- this is your code
execute immediate 'create table smap1(nam varchar2(10))'; -- correct code, no semicolon at end
But there's another problem.
You need to understand how substitution variables (&variable) works
SQL*Plus will prompt for substituion variables only once: just before the script compiles, before running it. And then the variables are replaced in the script verbatim, after which it will get compiled and executed.
For example, when you run your script, SQL*Plus recognizes that there are two unknown literals (&colname and &coldata), and will prompt for you. If you supply the values 'age', and 'number' for them, SQL*Plus will rewrite the script like this:
declare
-- omitted to add clarity
begin
execute immediate 'create table smap1(nam varchar2(10));';
if(no_of_cols>=2) then
for i in 2..no_of_cols loop
colname:=age;
coldata:=number;
execute immediate 'alter table smapl add '||colname||' '||coldata;
end loop;
end if;
end;
So if you want to assign a string literal to a variable, and you want to get that string from a substitution variable, you need to do this:
colname varchar2(30) := '&colname'; -- notice the single quotes
Assuming you provided 'age' for colname SQL*Plus will happily convert this to:
colname varchar2(30) := 'age';
So, placing a substitution variable inside a loop will not make SQL*Plus repeatedly prompt you for it's value.

Answer 2

For better understanding and analyze you should do it like this:
sqlcmd varhchar(30000);
begin
sqlcmd := 'create table smap1(nam varchar2(10))';
DBMS_OUTPUT.PUT_LINE(sqlcmd);
execute immediate sqlcmd;
if(no_of_cols>=2) then
for i in 2..no_of_cols loop
age :=&age;
datf:=&datf;
colname:=age;
coldata:=datf;
sqlcmd := 'alter table smapl add '||colname||' '||coldata;
DBMS_OUTPUT.PUT_LINE(sqlcmd);
execute immediate sqlcmd;
end loop;
end if;