ZConnection.UseMetadata, what is it for?

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Quick Info:
-We made two new drivers: odbc(raw and unicode version) and oledb
-GUID domain/field-defined support for FB
-extended error infos of Firebird
-performance ups are still in queue
In future some more feature will arrive, so stay tuned and don't hassitate to help
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hamacker
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ZConnection.UseMetadata, what is it for?

Post by hamacker »

There is a property ZConnection.UseMetadata that can be enabled or disable, what is it for?
Is for my application to consume something?

I´am learning about zeo to create this page to help brazilian comunity:
https://gladiston.net.br/?page_id=757
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aehimself
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Re: ZConnection.UseMetadata, what is it for?

Post by aehimself »

Hello,

Fresh from the source:

Code: Select all

    /// <summary>Are metadata used? If <c>True</c> then we can determine if
    ///  columns are writeable or not. This is required for generating automatic
    ///  updates.</summary>
    /// <returns><c>True</c> if metainformations are turned on; <c>False</c>
    ///  otherwise.</returns>
Just a small heads-up, you mention Zeos 7.3 in your article but that version never officially existed.
Delphi 12.2, Zeos 8 from latest GIT snapshot
Using:
- MySQL server 8.0.18; libmysql.dll 8.0.40 x64 5.7.19 x68, libmariadb.dll 3.3.11
- Oracle server 11.2.0, 12.1.0, 19.0.0; oci.dll 21.15
- MSSQL 2012, 2019; sybdb.dll FreeTDS_3102
- SQLite 3.47
marsupilami
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Re: ZConnection.UseMetadata, what is it for?

Post by marsupilami »

Hello,

UseMetadata tells Zeos drivers to not fetch metadata from the database. Some drivers need metadata at some point to get enough information for building insert / update / delete statements. So usually it is best to keep this option enabled. Otherwise Zeos could behave unexpectedly like not being able to determine field types correctly or making all data sets read only. Disabling UseMetadata can help in some rare corner cases.

Best regards,

Jan
hamacker
Junior Boarder
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Joined: 13.10.2021, 15:15

Re: ZConnection.UseMetadata, what is it for?

Post by hamacker »

I fix my article:
https://gladiston.net.br/?page_id=757

More late, I will translate to english.
Thank you guys.
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aehimself
Zeos Dev Team
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Posts: 798
Joined: 18.11.2018, 17:37
Location: Hungary

Re: ZConnection.UseMetadata, what is it for?

Post by aehimself »

Thank you for using, advertising and helping others to be able to use Zeos :)
Delphi 12.2, Zeos 8 from latest GIT snapshot
Using:
- MySQL server 8.0.18; libmysql.dll 8.0.40 x64 5.7.19 x68, libmariadb.dll 3.3.11
- Oracle server 11.2.0, 12.1.0, 19.0.0; oci.dll 21.15
- MSSQL 2012, 2019; sybdb.dll FreeTDS_3102
- SQLite 3.47
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