using fetch all = false

[digdagdigedag]

dear all,

1. it says in the doumentation of MyTable that one need to create a second connection to the MySql server when using fetch all = false.
what to do with this second connection ??? or is it enough if i just keep a second connection hanging around idly ?

2. when using fecth all = false, what exactly happens when i activate MyTable and move from record to record with Next() ? will the program load only those records into memory which are needed and unload as soon as they are not within scope of my cursor ?

3. does anybody have a small example application which is using fetch all = false ?

thanks
uwe

[Antaeus]

1. it says in the doumentation of MyTable that one need to create a second connection to the MySql server when using fetch all = false.
what to do with this second connection ??? or is it enough if i just keep a second connection hanging around idly ?
uwe

You should do nothing with the second connection. MyDAC manages it itself. MyDAC Dataset initiates creating this connection on opening in FetchAll=False mode, uses it to fetch records asynchronous, closes it when all records are fetched.

2. when using fecth all = false, what exactly happens when i activate MyTable and move from record to record with Next() ? will the program load only those records into memory which are needed and unload as soon as they are not within scope of my cursor ?
uwe

When you open a dataset in FetchAll=False mode, it fetches several records (use the FetchRows property to specify records count to fetch in one fetch operation). If you try to browse records that are not already cached, TMyQuery fetches on more batch of records, etc.

3. does anybody have a small example application which is using fetch all = false ?
uwe

Take a look at the Query demo that is a part of MyDACDemo.

[digdagdigedag]

Take a look at the Query demo that is a part of MyDACDemo.

i checked all Apps of MyDacDemo but could not find anyone using FetchAll = false

should i simply place a second TMyConnection component, clone all the properties from the first one, activate and leave it running without connecting it to any other component ?

thanks
uwe

[Antaeus]

i checked all Apps of MyDacDemo but could not find anyone using FetchAll = false

There is the check box that manages FetchAll mode for the query in the Query demo. If this check box is unchecked, MyQuery works in FetchAll=False mode.

should i simply place a second TMyConnection component, clone all the properties from the first one, activate and
leave it running without connecting it to any other component ?

No, you should do nothing. This is done by MyDAC automatically.