| Subject | Re: Copy an image field from one table to another |
| From | roy price <royprice@royprice.name> |
| Date | Fri, 16 Apr 2021 23:03:35 -0400 |
| Newsgroups | dbase.getting-started |
Mervyn Bick Wrote: > On 2021/04/16 11:18, roy price wrote: > > Hello Again, > > I was gaily adding additional photos to my file photos03, when I came across the message "Database engine fail" (not sure of the exact wording). > > I presume that means a corrupted file > > So I've gone back and copied a backup file, and wrote a small program to compare both files and add (the additional) records from the problem file to the backup file. > > As in select 1, fields to memory, select 2, and copy memory items to appended records. Then I realised that I do not know how to copy the binary field that way . > > Any suggestions? > > Regards > > Roy Price > > Thanks Mervyn, I managed to get a non-corrupted version reconstructed with your help, starting with a backup from a while ago, the subsequent backups also had the same problem. The file mostly worked, hiding the problem, it was only when I tried to copy it to another name that the failure occurred. Regards Roy Price > > If the photos03 table is corrupted it may not be possible to use it. On > the other hand, if you've been able to open the table by double-clicking > on it in the Navigator then all may not be lost. > > One can't simply use replace a->fieldname with b->fieldname for a binary > (non text) field. The only way to get an image from one table to > another if one is not copying the entire table is to export the image to > a file and then load that file into the new file. > > An added complication is if you have used an autoinc field as the id for > the images. One can't save a value to an autoinc field. One has to > append a blank record which will allow dBASE to assign a value to the > field. > > Firstly, before you try anything you must only be working with copies of > the old backup table and photo03. > > The following little program should do the job. Copy and paste it into > a new program file. Before you use it you must make sure that the > correct table names are used and that the correct number for the image > field is used. Change anything that is incorrect. > > ******** Start of program ******** > cSource = 'photo03' //the damaged table which would not accept entries. > cTarget = 'backup01' //the old backup table which doesn't include > //the latest images > > //Edit the lines above to show the correct table names. > > //set up the damaged file which has images not previously saved > //to a backup > q = new query() > q.sql = 'select * from ' + cSource > q.active = true > //set up target file i.e the old backup which does not have all the images > q1 = new query() > q1.sql = 'select * from ' + cTarget > q1.active = true > //go to the bottom of the target table and save ID value for the > //last record. This will be used to find the corresponding record > //in photo03. > q1.rowset.last() > nId = q1.rowset.fields['id'].value > //Find that record in the source table > q.rowset.applyLocate( "id = " + nId ) > //Goto the next record i.e the first record not already in the target > // table > q.rowset.next() > do while not q.rowset.endofset > q1.rowset.beginAppend() //add a blank record > //we can't place a value in an auto inc field so skip 1st field > for n = 2 to q.rowset.fields.size > if n = 2 //the image field > // Make sure you have the correct field here. > if file('temp_image') //Note: No dot > erase temp_image > endif > q.rowset.fields[n].copyToFile('temp_image.') > //Note: Dot at end of name > q1.rowset.fields[n].replaceFromFile('temp_image.') > else > q1.rowset.fields[n].value = q.rowset.fields[n].value > endif > next > q1.rowset.save() // save the new record > //go to the next record in the source table > q.rowset.next() > enddo > q.active = false > q1.active = false > ******* End of program ********** > > Mervyn. > > > > > > > > | |