Audit Triggers Problem

Im using triggers to track changes Insert/Update/Deletes on my DB tables and they work for when i am manually adding/editing and deleting a single records.

The problem arises in that I have an asset/inventory management app that dumps lots of details into my DB tables at once each time its run.
Not all of the tables are updated and data cannot be completely inserted.

This is the trigger i have been using - could someone tell me how to modify it to work.



/*
This trigger audit trails all changes made to a table.
It will place in the table Audit all inserted, deleted, changed columns in the table on which it is placed.
It will put out an error message if there is no primary key on the table
You will need to change @TableName to match the table to be audit trailed
*/

ALTER trigger tr_TableName
on dbo.TableName for insert, update, delete
as

declare @bit int ,
@field int ,
@maxfield int ,
@char int ,
@fieldname varchar(128) ,
@TableName varchar(128) ,
@PKCols varchar(1000) ,
@sql varchar(2000),
@UpdateDate varchar(21) ,
@Action nvarchar(50) ,
@HostName nvarchar(50),
@PKFieldName varchar (1000)


IF EXISTS(SELECT * FROM inserted)
IF EXISTS(SELECT * FROM deleted)
--update = inserted and deleted tables both contain data
BEGIN
SET @Action = 'UPDATE'
SELECT @DeviceID = (SELECT inserted.DeviceID FROM inserted INNER JOIN deleted ON inserted.deviceID = deleted.deviceid)
END
ELSE

--insert = inserted contains data, deleted does not
BEGIN
SET @Action = 'INSERT'
select @DeviceID = (SELECT DeviceID from inserted)
END
ELSE
--delete = deleted contains data, inserted does not
BEGIN
SET @Action = 'DELETE'
select @DeviceID = (SELECT DeviceID from deleted)
END

select @TableName = 'TableName'

-- date
select @HostName = host_name(),
@UpdateDate = convert(varchar(8), getdate(), 112) + ' ' + convert(varchar(12), getdate(), 114),
--@DeviceID,
@PKFieldName=(select top 1 c.COLUMN_NAME fromINFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,INFORMATION_SCHEMA.KEY_COLUMN_USAGE c where pk.TABLE_NAME = @TableName
andCONSTRAINT_TYPE = 'PRIMARY KEY'andc.TABLE_NAME = pk.TABLE_NAME and c.CONSTRAINT_NAME = pk.CONSTRAINT_NAME)

-- get list of columns
select * into #ins from inserted
select * into #del from deleted

-- Get primary key columns for full outer join
select@PKCols = coalesce(@PKCols + ' and', ' on') + ' i.' + c.COLUMN_NAME + ' = d.' + c.COLUMN_NAME
fromINFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,
INFORMATION_SCHEMA.KEY_COLUMN_USAGE c
where pk.TABLE_NAME = @TableName
andCONSTRAINT_TYPE = 'PRIMARY KEY'
andc.TABLE_NAME = pk.TABLE_NAME
andc.CONSTRAINT_NAME = pk.CONSTRAINT_NAME

if @PKCols is null
begin
raiserror('no PK on table %s', 16, -1, @TableName)
return
end

select @field = 0, @maxfield = max(ORDINAL_POSITION) from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = @TableName
while @field < @maxfield
begin
select @field = min(ORDINAL_POSITION) from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = @TableName and ORDINAL_POSITION > @field
select @bit = (@field - 1 )% 8 + 1
select @bit = power(2,@bit - 1)
select @char = ((@field - 1) / 8) + 1
--if substring(COLUMNS_UPDATED(),@char, 1) & @bit > 0
begin
select @fieldname = COLUMN_NAME from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = @TableName and ORDINAL_POSITION = @field
select @sql = 'insert LITE_Inventory (TableName, FieldName, OldValue, NewValue, UpdateDate, Action, Host, PkFieldName, DeviceID)'
-- select @sql = 'insert LITE_Inventory (TableName, FieldName, OldValue, NewValue, UpdateDate, Action, Host, PkFieldName)'
select @sql = @sql + ' select ''' + @TableName + ''''
select @sql = @sql + ',''' + @fieldname + ''''
select @sql = @sql + ',convert(varchar(1000),d.' + @fieldname + ')'
select @sql = @sql + ',convert(varchar(1000),i.' + @fieldname + ')'
select @sql = @sql + ',''' + @UpdateDate + ''''
select @sql = @sql + ',''' + @Action + ''''
select @sql = @sql + ',''' + @HostName + ''''
select @sql = @sql + ',''' + @PKFieldName + ''''
select @sql = @sql + ' from #ins i full outer join #del d'
select @sql = @sql + @PKCols
select @sql = @sql + ' where i.' + @fieldname + ' <> d.' + @fieldname
select @sql = @sql + ' or (i.' + @fieldname + ' is null and d.' + @fieldname + ' is not null)'
select @sql = @sql + ' or (i.' + @fieldname + ' is not null and d.' + @fieldname + ' is null)'

exec (@sql)
end
end