Exception when changing field type from DateTime to Date

Exception when changing field type from DateTime to Date

Postby Guest » Tue 18 Jan 2005 15:10

Hello,

I'm having this issue (FYI it's working well with zeoslib comp).

1: Create a simple table with a TDateTime field.
2: Create a simple delphi project with a grid connected with this table
Retreive at design time the fields.
Compile and launch the project, insert a row, go into the DateTimeField, put a value and post.... (it will works). Close the project.

3: Now, with your favorite DBA tool,open the mysql table and change the DateTime field to an DateField.

4: Launch the project again, insert a new row and go into the DateTimeField.... you will raise an exception (0.0 is not a correct time).

As said before, I don't have this behaviour with other mysql compatible components. It is possible to change this behaviour ?

Thank you very much.

Stephan
Guest
 

Re: Exception when changing field type from DateTime to Date

Postby Ikar » Wed 19 Jan 2005 09:45

MyDAC doesn't support such conversion.
Most likely that Zeos uses the same field type for DATE and DATETIME fields.
Ikar
 
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Postby Guest » Wed 19 Jan 2005 09:48

Thank you for your reply Ikar, but isn't it possible to implement it ?
Guest
 

Postby Ikar » Thu 20 Jan 2005 15:03

This task is quite difficult. More over it is complicated by possible cases of fields conversion. For example, to implement conversion DATE <-> DATETIME is quite easy, DATE <-> CHAR is more difficult, but DATE <-> BOOL unlikely possible at all.

Please specify a situation for that you need these conversions.
Ikar
 
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Postby swierzbicki » Thu 27 Jan 2005 13:29

For performances issues, I have downgraded some DateTime fields to DateField. (widely used in about 80 tables). With this possibility, I will not have to re-compile my project. It will be a time saving thing for me (but perhaps not for you).
swierzbicki
 
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Postby Ikar » Thu 27 Jan 2005 15:52

Beside time waste we would like to avoid unnecessary extending the functionality that might cause errors in debugged long ago cases.
Ikar
 
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