[T-SQL] Database backup procedure - advanced

I have got this script from one of the blogs:

if exists (select * from sysobjects where id = object_id(N'[dbo].[spBackupAllDatabases]') and OBJECTPROPERTY(id, N'IsProcedure') = 1)
drop procedure [dbo].[spBackupAllDatabases]
go

Create Procedure spBackupAllDatabases
@Path varchar(128) ,
@Type varchar(4) -- Full / Log
as
/*
Backup file format
_Full_yyyymmdd_hhmmss.bak
_Log_yyyymmdd_hhmmss.bak

exec spBackupAllDatabases 'c:\SQLBackups\', 'Full'
*/
/*
drop table DatabaseBackup

Create table DatabaseBackup
(
Name varchar(128) primary key nonclustered ,
BackupFlagFull varchar(1) not null check (BackupFlagFull in ('Y','N')) ,
BackupFlagLog varchar(1) not null check (BackupFlagLog in ('Y','N')) ,
RetentionPeriodFull datetime not null ,
RetentionPeriodLog datetime not null
)
*/
set nocount on
declare @sql varchar(1000)

-- Get all database names
create table #DBName
(
ID int identity (1,1) ,
Name varchar(128) not null ,
RetentionPeriod datetime null
)

insert #DBName
(Name)
select name
from master..sysdatabases

-- Include any new databases in the backup
insert DatabaseBackup
(
Name ,
BackupFlagFull ,
BackupFlagLog ,
RetentionPeriodFull ,
RetentionPeriodLog
)
select #DBName.Name ,
'Y' ,
'N' ,
'7 jan 1900' , -- default one week
'1 jan 1900'
from #DBName
left outer join DatabaseBackup
on DatabaseBackup.Name = #DBName.Name
where DatabaseBackup.Name is null
and lower(#DBName.Name) <> 'tempdb'

-- Remove any non-existant databases
delete DatabaseBackup
where not exists
(
select *
from #DBName
where #DBName.Name = DatabaseBackup.Name
)

delete #DBName

create table #ExistingBackups
(
Name varchar(128) ,
ID int identity (1,1)
)

-- loop through databases
declare @Name varchar(128) ,
@RetentionPeriod datetime ,
@LastBackupToKeep varchar(8) ,
@ID int ,
@MaxID int

insert #DBName
(Name, RetentionPeriod)
select Name, case when @Type = 'Full' then RetentionPeriodFull else RetentionPeriodLog end
from DatabaseBackup
where (@Type = 'Full' and BackupFlagFull = 'Y')
or (@Type = 'Log' and BackupFlagLog = 'Y')

select @MaxID = max(ID) ,
@ID = 0
from #DBName

while @ID < @MaxID begin -- get next database to backup select @ID = min(ID) from #DBName where ID > @ID

select @Name = Name ,
@RetentionPeriod = RetentionPeriod
from #DBName
where ID = @ID

-- Delete old backups
delete #ExistingBackups
select @sql = 'dir /B ' + @Path
select @sql = @sql + @Name + '_' + @Type + '*.*'

insert #ExistingBackups exec master..xp_cmdshell @sql

if exists (select * from #ExistingBackups where Name like '%File Not Found%')
delete #ExistingBackups

select @LastBackupToKeep = convert(varchar(8),getdate() - @RetentionPeriod,112)
delete #ExistingBackups where Name > @Name + '_' + @Type + '_' + @LastBackupToKeep

declare @eID int ,
@eMaxID int ,
@eName varchar(128)

-- loop round all the out of date backups
select @eID = 0 ,
@eMaxID = coalesce(max(ID), 0)
from #ExistingBackups

while @eID < @eMaxID begin select @eID = min(ID) from #ExistingBackups where ID > @eID
select @eName = Name from #ExistingBackups where ID = @eID

select @sql = 'del ' + @Path + @eName
exec master..xp_cmdshell @sql
end
delete #ExistingBackups

-- now do the backup
select @sql = @Path + @Name + '_' + @Type + '_'
+ convert(varchar(8),getdate(),112) + '_'
+ replace(convert(varchar(8),getdate(),108),':','') + '.bak'
if @Type = 'Full'
backup database @Name
to disk = @sql
else
backup log @Name
to disk = @sql
end

go