update SQLite database using insert

3 Ansichten (letzte 30 Tage)
Charles
Charles am 18 Sep. 2017
Bearbeitet: Guillaume am 22 Sep. 2017
Hello I am trying to update my SQLite database using the following command
insert(conn, 'ClosePriceTable', {'Dates','AUD_CAD', 'AUD_CHF'}, Table_New_datax(2:end,:))
However I rather want to update only if new records are different to current records. Thus I do not want duplicate records in my SQLite database. If the new records are the same as current records then I merely wish to overwrite and not insert the same record again.
The key variable differentiating records is the date.
How can I avoid duplication of records? What command can I use?

Antworten (1)

Han Du
Han Du am 22 Sep. 2017
Duplicates can be avoid by setting Dates to UNIQUE in your query to create the table.
  2 Kommentare
Charles
Charles am 22 Sep. 2017
Csn you provide an example as I am new to SQL
Guillaume
Guillaume am 22 Sep. 2017
Bearbeitet: Guillaume am 22 Sep. 2017
See the SQLite doc
Something like:
CREATE TABLE yourtable (Dates UNIQUE ON CONFLICT REPLACE, ...)
when you create the table.
Note that the ON CONFLICT REPLACE is particular to SQLite, it is not standard SQL. Other database engines will abort the transaction instead of replacing the existing row by your new values. Therefore the other way to do what you want is to first check if your keys already exist in database and do an UPDATE for the ones that do.

Melden Sie sich an, um zu kommentieren.

Produkte

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by