How can i control the DataBase

MIT App Inventor Help
1

for a long time i am using visual basic. in visual basic i am kontroling the data base like this

for reading input
for writing output
for re writing append
and if i want to reach end of file i am using (eof)
commands.
in this app can you help me ?
how can i know files number ?
how can i reach end of file ?
how can i delete files from the database ?
as you understand i want to control data base Plesa help me.

2

What database ? Where ?

3

Choosing a database can be like choosing a weapon in a computer game.

Depending on what you are hunting, you may need to choose between

a sniper rifle (a highly indexed columnar table),
a shotgun (local temporary files)
a chainsaw (bulk loading)

So what kind of data are you hunting?

4

data
data984×704 159 KB

5

With your list text1, use these blocks to add or remove items:

lists_insert_item
lists_remove_item

then save the list back to the text file as a csv - overwriting the existing list

6

Can you upload test.txt so we can verify its structure?
I’m guessing it is a Comma Separated Values (csv) table, but need to be sure.

If you bring it into a global variable as a list of lists (table),
removing the 21st item is easy.

To display the table in multiple columns, you would need feed a copy of the table into something fancy that would wrap the data in html for a Web Viewer, or
copy out the 3 columns for side by side ListViews.

Th6e19773230855907ca6d94cddc48d80803025af8_2_690x493 e SelectionIndex gives you the item number to remove if you want to remove from a ListView or List Picker.

Also, it makes no sense to remove commas from the name of a file.