SET SERVEROUTPUT ON
DECLARE
   v_field_name    VARCHAR2 (50) := 'v_emp_id';
   v_compare       VARCHAR2 (50) := '=';
   v_value         VARCHAR2 (50) := '1234';
   v_emp_id        VARCHAR2 (50) := '1234';
   v_check         VARCHAR2 (5)  := 'FALSE';
   v_if_statement  VARCHAR2 (1000);
   v_sql_statement VARCHAR2 (1000);
BEGIN
   v_if_statement := 'IF '||v_field_name||' '||v_compare||' '||''''||v_value||''''||' '||
                     'THEN :v_check := ''TRUE'';'||' '||
                     'END IF;';
   
   v_sql_statement := 'BEGIN '||v_if_statement||' END;';
   
   --Remove any special characters
   v_sql_statement := REPLACE(REPLACE(REPLACE(v_sql_statement,CHR(10),' '),CHR(13),' '),CHR(9),' ');
   
   dbms_output.put_line('v_sql_statement : '||v_sql_statement);
   
   EXECUTE IMMEDIATE v_sql_statement USING v_check;
   
   dbms_output.put_line('v_check : '||v_check);
END;
/

DECLARE
*
ERROR at line 1:
ORA-06550: line 1, column 10:
PLS-00201: identifier 'V_EMP_ID' must be declared
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored
ORA-06512: at line 21

SCOTT@orcl_11gR2> SET SERVEROUTPUT ON
SCOTT@orcl_11gR2> DECLARE
  2  	v_field_name	VARCHAR2 (50) := 'v_emp_id';
  3  	v_compare	VARCHAR2 (50) := '=';
  4  	v_value 	VARCHAR2 (50) := '1234';
  5  	v_emp_id	VARCHAR2 (50) := '1234';
  6  	v_check 	VARCHAR2 (5)  := 'FALSE';
  7  	v_if_statement	VARCHAR2 (1000);
  8  	v_sql_statement VARCHAR2 (1000);
  9  BEGIN
 10  	v_if_statement := 'IF :'||v_field_name||' '||v_compare||' '||''''||v_value||''''||' '||
 11  			  'THEN :v_check := ''TRUE'';'||' '||
 12  			  'END IF;';
 13  
 14  	v_sql_statement := 'BEGIN '||v_if_statement||' END;';
 15  
 16  	--Remove any special characters
 17  	v_sql_statement := REPLACE(REPLACE(REPLACE(v_sql_statement,CHR(10),' '),CHR(13),' '),CHR(9),' ');
 18  
 19  	dbms_output.put_line('v_sql_statement : '||v_sql_statement);
 20  
 21  	EXECUTE IMMEDIATE v_sql_statement USING IN v_emp_id, OUT v_check;
 22  
 23  	dbms_output.put_line('v_check : '||v_check);
 24  END;
 25  /
v_sql_statement : BEGIN IF :v_emp_id = '1234' THEN :v_check := 'TRUE'; END IF;
END;
v_check : TRUE

PL/SQL procedure successfully completed.

SCOTT@orcl_11gR2>