日期:2014-05-16  浏览次数:20429 次

存储过程的运用之print_table
create or replace
procedure print_table
( p_query in varchar2,
  p_date_fmt in varchar2 default 'dd-mon-yyyy hh24:mi:ss' )
                                                                                 
                                           
-- this utility is designed to be installed ONCE in a database and used
-- by all.  Also, it is nice to have roles enabled so that queries by
-- DBA's that use a role to gain access to the DBA_* views still work
-- that is the purpose of AUTHID CURRENT_USER
AUTHID CURRENT_USER
is
    l_theCursor     integer default dbms_sql.open_cursor;
    l_columnValue   varchar2(4000);
    l_status        integer;
    l_descTbl       dbms_sql.desc_tab;
    l_colCnt        number;
    l_cs            varchar2(255);
    l_date_fmt      varchar2(255);
                                                                                 
                                           
    -- small inline procedure to restore the sessions state
    -- we may have modified the cursor sharing and nls date format
    -- session variables, this just restores them
    procedure restore
    is
    begin
       if ( upper(l_cs) not in ( 'FORCE','SIMILAR' ))
       then
           execute immediate
           'alter session set cursor_sharing=exact';
       end if;
       if ( p_date_fmt is not null )
       then
           execute immediate
               'alter session set nls_date_format=''' || l_date_fmt || '''';
       end if;
       dbms_sql.close_cursor(l_theCursor);
    end restore;
begin
    -- I like to see the dates print out with times, by default, the
    -- format mask I use includes that.  In order to be "friendly"
    -- we save the date current sessions date format and then use
    -- the one with the date and time.  Passing in NULL will cause
    -- this routine just to use the current date format
    if ( p_date_fmt is not null )
    then
       select sys_context( 'userenv', 'nls_date_format' )
         into l_date_fmt
         from dual;
                                                                                 
                                           
       execute immediate
       'alter session set nls_date_format=''' || p_date_fmt || '''';
    end if;
                                                                                 
                                           
    -- to be bind variable friendly on this ad-hoc queries, we
    -- look to see if cursor sharing is already set to FORCE or
    -- similar, if not, set it so when we parse -- literals
    -- are replaced with binds
    if ( dbms_utility.get_parameter_value
         ( 'cursor_sharing', l_status, l_cs ) = 1 )
    then
        if ( upper(l_cs) not in ('FORCE','SIMILAR'))
        then
            execute immediate
           'alter session set cursor_sharing=force';
        end if;
    end if;
                                                                                 
                                           
    -- parse and describe the query sent to us.  we need
    -- to know the number of columns and their names.
    dbms_sql.parse(  l_theCursor,  p_query, dbms_sql.native );
    dbms_sql.describe_columns
    ( l_theCursor, l_colCnt, l_descTbl );
                                                                                 
                                           
    -- define all columns to be cast to varchar2's, we
    -- are just printing them out
    for i in 1 .. l_colCnt loop
        if ( l_descTbl(i).col_type not in ( 113 ) )
        then
            dbms_sql.define_column
            (l_theCursor, i, l_columnValue, 4000);
        end if;
    end loop;
                                                                                 
                                           
    -- execute the query, so we can fetch
    l_status := dbms_sql.execute(l_theCursor);