Use dbms_sql.describe_columns : DBMS_SQL « System Packages « Oracle PL/SQL Tutorial






SQL>
SQL> CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
  2                    ENAME VARCHAR2(10),
  3                    JOB VARCHAR2(9),
  4                    MGR NUMBER(4),
  5                    HIREDATE DATE,
  6                    SAL NUMBER(7, 2),
  7                    COMM NUMBER(7, 2),
  8                    DEPTNO NUMBER(2));

Table created.

SQL>
SQL>
SQL> INSERT INTO EMP VALUES (7369, 'SMITH', 'CLERK',    7902, TO_DATE('17-DEC-1980', 'DD-MON-YYYY'), 800, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7499, 'ALLEN', 'SALESMAN', 7698, TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600, 300, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7521, 'WARD',  'SALESMAN', 7698, TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250, 500, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7566, 'JONES', 'MANAGER',  7839, TO_DATE('2-APR-1981',  'DD-MON-YYYY'), 2975, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7654, 'MARTIN', 'SALESMAN', 7698,TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7698, 'BLAKE', 'MANAGER', 7839,TO_DATE('1-MAY-1981', 'DD-MON-YYYY'), 2850, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7782, 'CLARK', 'MANAGER', 7839,TO_DATE('9-JUN-1981', 'DD-MON-YYYY'), 2450, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7788, 'SCOTT', 'ANALYST', 7566,TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7839, 'KING', 'PRESIDENT', NULL,TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7844, 'TURNER', 'SALESMAN', 7698,TO_DATE('8-SEP-1981', 'DD-MON-YYYY'), 1500, 0, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7876, 'ADAMS', 'CLERK', 7788,TO_DATE('12-JAN-1983', 'DD-MON-YYYY'), 1100, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7900, 'JAMES', 'CLERK', 7698,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 950, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7902, 'FORD', 'ANALYST', 7566,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7934, 'MILLER', 'CLERK', 7782,TO_DATE('23-JAN-1982', 'DD-MON-YYYY'), 1300, NULL, 10);

1 row created.

SQL>
SQL> set echo on
SQL>
SQL> create or replace procedure  desc_query( p_query in varchar2 )
  2  is
  3      l_columnValue   varchar2(4000);
  4      l_status        integer;
  5      l_colCnt        number default 0;
  6      l_cnt           number default 0;
  7      l_line          long;
  8      l_descTbl       dbms_sql.desc_tab;
  9      l_theCursor     integer default dbms_sql.open_cursor;
 10  begin
 11      dbms_sql.parse(  l_theCursor,  p_query, dbms_sql.native );
 12      dbms_sql.describe_columns( c       => l_theCursor,
 13                                 col_cnt => l_colCnt,
 14                                 desc_t  => l_descTbl );
 15
 16      for i in 1 .. l_colCnt
 17      loop
 18          dbms_output.put_line( 'Column Type:' || l_descTbl(i).col_type );
 19          dbms_output.put_line( 'Max Length:' || l_descTbl(i).col_max_len );
 20          dbms_output.put_line( 'Name:' || l_descTbl(i).col_name );
 21          dbms_output.put_line( 'Name Length:' || l_descTbl(i).col_name_len );
 22          dbms_output.put_line( 'ObjColumn Schema Name.' || l_descTbl(i).col_schema_name );
 23          dbms_output.put_line( 'Schema Name Length:' || l_descTbl(i).col_schema_name_len );
 24          dbms_output.put_line( 'Precision:' || l_descTbl(i).col_precision );
 25          dbms_output.put_line( 'Scale:' || l_descTbl(i).col_scale );
 26          dbms_output.put_line( 'Charsetid:' || l_descTbl(i).col_Charsetid );
 27          dbms_output.put_line( 'Charset Form:' || l_descTbl(i).col_charsetform );
 28          if ( l_desctbl(i).col_null_ok ) then
 29              dbms_output.put_line( 'Nullable:Y' );
 30          else
 31              dbms_output.put_line( 'Nullable:N' );
 32          end if;
 33       end loop;
 34      dbms_sql.close_cursor(l_theCursor);
 35  exception
 36      when others then dbms_sql.close_cursor( l_theCursor );
 37          raise;
 38  end desc_query;
 39  /

Procedure created.

SQL>
SQL> set serveroutput on
SQL> exec desc_query( 'select rowid, ename from emp' );
Column Type:11
Max Length:16
Name:ROWID
Name Length:5
ObjColumn Schema Name.
Schema Name Length:0
Precision:0
Scale:0
Charsetid:0
Charset Form:0
Nullable:N
Column Type:1
Max Length:10
Name:ENAME
Name Length:5
ObjColumn Schema Name.
Schema Name Length:0
Precision:0
Scale:0
Charsetid:178
Charset Form:1
Nullable:Y

PL/SQL procedure successfully completed.

SQL>
SQL>
SQL> drop table emp;

Table dropped.

SQL>








31.26.DBMS_SQL
31.26.1.dbms_sql.number_table
31.26.2.Close a cursor
31.26.3.Assign date with DBMS_SQL package
31.26.4.Create Pl/SQL block dynamically and then execute it by calling 'DBMS_SQL.EXECUTE'
31.26.5.DBMS_SQL.PARSE
31.26.6.An example of using DBMS_SQL.OPEN_CURSOR
31.26.7.Package for running dynamic sql based on DBMS_SQL package
31.26.8.Wrap dbms_sql package
31.26.9.Dump Column long with DBMS_SQL.DEFINE_COLUMN_LONG
31.26.10.DBMS_SQL.BIND_VARIABLE and DBMS_SQL.EXECUTE
31.26.11.DBMS_SQL.EXECUTE an update statement
31.26.12.Use DBMS_SQL to update a table and get the number of rows updated
31.26.13.DBMS_SQL.VARCHAR2_TABLE and DBMS_SQL.NUMBER_TABLE
31.26.14.Use dynamic SQL to check the business logic
31.26.15.Use DBMS_SQL package to parse math expression
31.26.16.Use a character string of arithmetic logic, selecting against the DUAL table to return a number value.
31.26.17.DBMS_SQL.LAST_ERROR_POSITION
31.26.18.Dump query with dbms_sql
31.26.19.Use dbms_sql.describe_columns
31.26.20.Print table with dynamic query