Sending date and time information from Android to MySQL

Dates always seem to trip me up. The app that I am currently working on needs to send records from Android to a MySQL back end. The records contain date and time information. The records initially go into a SQLite db on the phone. From there they are read and sent to the back end one at a time and cancelled off the list when sending has been successful. So the problem comes down to putting a date and time into sqlite. Taking that date and time out and sending it across the network to be inserted into MySQL. Here is a synopsis of what I did to get this to work:
Create a table on sqlite (column types are largely irrelevant here, so just leave them out).
Create a table on mysql (the target) and specify a column type of timestamp for the date and time info.
Create a java.util.Date object to get the current time. Using a SimpleDateFormatter format this for insertion into the sqlite db.
Next read this row back.
Send this value across the network.
At the Mysql end use a prepared statement to do the insert and set the value of the date and time column like this:

stmt.setTimestamp(4, new java.sql.Timestamp(SDF.parse(phoneTime).getTime()));


That's it. If you try to use a java.sql.Date type for the insert you lose the time information. Otherwise that works fine. 
This is better than just inserting strings as you can now do stuff like order by that column. If it is strings, that is a much trickier proposition.

Comments

Post a Comment

Popular posts from this blog

Building a choropleth map for Irish agricultural data

I wanted to create a choropleth map  using Irish data. The Irish Government has made a large quantity of data available at data.gov.ie. The set I chose was for Bovine TB across Ireland over a number of years. You can get geojson for a variety of countries and Ireland's county boundaries are available. All I had to do was get the data labels to match. In the data some counties are split into 2 parts. I merged and summed these data points to get the choropleth to work with normal county boundaries. You can see the results here . A link to the github is included at the top of the notebook.
Read more

Early Stopping with Keras

Steps to train a model There are a number of things you have to do when working on a Machine Learning problem. Import your data and transform it as appropriate Define  your model using something like Keras - this includes your chosen hyperparameter values Run the training phase Evaluate the model If at the end of this process the evaluation shows that your model is not sufficient for your needs you will need to make some changes and rerun the training.  Ideally you should have a way to spot that training is not going as you want and stop it. This is one of the uses of early stopping. The other is if your model has reached a sufficient quality standard for you to use and further improvements have slowed, stopped altogether or an unnecessary.  Early Stopping Keras provides a way of doing this using the EarlyStopping callback . There are a range of callbacks in Keras and you can define your own. Details are here . The EarlyStopping callback works by choosing a metric
Read more

AutoCompleteTextView backed with data from SQLite in Android

Image
This is a handy piece of code. As your database gets bigger you can allow the user to pick the correct value by typing. If the db gets very big, you can always increase the threshold, so that the query does not run until there will be a suitably sized resultset returned. Running it at a threshold of 1 is fine for very small resultsets.  Here is the code you need to back your AutoCompleteTextView with a cursor adapter. @Override protected void onResume() { super.onResume(); text = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView1); final AdapterHelper h = new AdapterHelper(this); Cursor c = h.getAllResults(); startManagingCursor(c); String[] from = new String[] { "val" }; int[] to = new int[] { android.R.id.text1 }; CursorAdapter adapter = new MyCursorAdapter(this, android.R.layout.simple_dropdown_item_1line, c, from, to); adapter.setFilterQueryProvider(new FilterQueryProvider() { public Cursor runQuery(Cha
Read more