Maximum No of Records - Plus Unique Field Type

Discuss plans for a future version of HanDBase for the Google Android platform

Maximum No of Records - Plus Unique Field Type

Postby MidlandDeltic » Mon Mar 25, 2019 8:12 am

Hi

A couple of related issues. Firstly I cannot find a figure for the maximum number of records in a single database. The fact that the unique field type only goes up to 65536 suggests that is the limit. Can you confirm please?

While mentioning the Unique Field type, can you confirm how this works please? In Palm I seem to recall that the number was unique across all databases, and thought this appeared to be the case on Android. However, when cross referencing data recently, I find that I have duplicated "unique" numbers in different databases, despite them being getting different number blocks to start with when the Unique field was set up. Is there any way I can force unique numbers across all databases? The toal number if records is approaching thay apoarent 65k limit ;)

Thanks

Sean

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Re: Maximum No of Records - Plus Unique Field Type

Postby ddhsoftwareadmin » Sat Mar 30, 2019 12:58 pm

Hi Sean,

Thanks for writing. The max number of records are 65000 per database. The unique field is unique only within the current database- the unique counter is kept as part of the database structure, and it is shared among all fields in that database. So if you have 3 unique fields, you'll notice it increasing by 3 for each record you add!

Hope this helps.
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Re: Maximum No of Records - Plus Unique Field Type

Postby MidlandDeltic » Sun Mar 31, 2019 9:18 am

Thanks David. I may need to review my database structure, as there are (currently) over 10000 records, and each has a series of "history" records in a daughter database which can be up 15 or more per record (eg new, change owner, reregistration, scrapping). A pity as I wanted to retain all history events in one database for each category I record to allow a view of the complete history in a single link.

BTW, can you clarify what counts as a unique field please? In the database I am currently expanding, it is indeed incrementing three for each record, but I only have one field set as the Unique type. Of 32 fields, there are DB Pop Up (5), Text (11), Check Box (3), Date (3), Pop Up (5) Link (2), Linked (1), Unique (1), and Integer (1).

Many thanks.

Regards

Sean
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Re: Maximum No of Records - Plus Unique Field Type

Postby mjhanna » Sun Mar 31, 2019 7:00 pm

Sean,

I am not sure exactly what you are trying to do, but it is possible HanDBase's "unique" field type may not a good candidate for doing something like what you are trying to do with daughter databases. I suggest you read the (old) Forum thread about "Automatically generating a Unique, Static, "Key" field" which I started here some time back. Be sure to read the entire thread as Dave and Brian both replied with some warnings and issues concerning the method I described. However, if you understand those warnings I think it might be a way to generate a unique "Record Number" which can be used across your main and daughter databases for each of your records.

Hope this gives you ideas,
Michael
(Only a user and not affiliated with DDH Software, but working with computer databases for over fifty years.)
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Re: Maximum No of Records - Plus Unique Field Type

Postby MidlandDeltic » Tue May 21, 2019 8:18 am

mjhanna wrote:Sean,

I am not sure exactly what you are trying to do, but it is possible HanDBase's "unique" field type may not a good candidate for doing something like what you are trying to do with daughter databases. I suggest you read the (old) Forum thread about "Automatically generating a Unique, Static, "Key" field" which I started here some time back. Be sure to read the entire thread as Dave and Brian both replied with some warnings and issues concerning the method I described. However, if you understand those warnings I think it might be a way to generate a unique "Record Number" which can be used across your main and daughter databases for each of your records.

Hope this gives you ideas,


Hi Michael

Sorry for the delay in responding - I didn't get a notification in Tapatalk!

In part I am future proofing - by putting in a unique identifier for each vehicle, be it railway locomotive, bus, aircraft etc, and ensuring all daughter records have it will allow easier tie up if I have to export data out to start again. The things you think of several years down the line :)

The parent databases are the vehicles - so to take one we have each vehicle with it's own record. A daughter database "History" has all changes to the vehicle - for example, date of registration, joining fleet, leaving fleet, change of fleet number, delicensing, scrapping; a "Sighting" database and a "Travelled" one. Given a vehicle can easily have 20 or more entries, when I have 10000+ vehicles in a database I could easily hit the limit. There is also a "Photo" database, which has all photos taken regardless of type, with parent - child link to each vehicle database. This is where I found that the Unique field was not unique across databases, as duplicate numbers were cropping up as I entered the different vehicle types.

I suspect I will need to restart from the ground up to come up with a solution; I'm not a database expert, and this has grown from my original tinkerings in Palm days - in particular the advent of digital photography has increased the number of shots per trip drastically :) Hence my current task of ensuring a sort key is available across all records, so any .csv export can be rejoined in future.

I hope that makes some sort of sense!

Cheers

Sean
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