CODEWITHSUNDEEP
androidsqlite
YFeizi
YFeizi

Reputation: 1528

Why selectionArgs must be an String array?

I answered a question in stack overflow and the user that asked the question ask me:
SQlite Query in android using cursor

why i must give my selectionArgs an Array instead its a single value ?

I didn't think about this before and its my question too now. We must use an array when we have only one value for selectionArgs in DB query?
(I hope i right my question in right place)

Upvotes: 1

Views: 1560

Answers (1)

hungryghost
hungryghost

Reputation: 9673

Here's the relevant documentation. Basically, String[] selectionArgs is an array so you can have one or more arguments for your sql WHERE clause. Since these parameters are used in the database.query() method, they're actually building a raw sql query string to be run by SQLite. In the String selection parameter, you specify all the WHERE clause column names, like this:

String selection = "DefaultId =? OR Name=?";

For every ? in selection, a corresponding WHERE value is substituted from your selectionArgs array. So, you should have something like this:

String[] selectionArgs = new String[]{"567", "Bob"};

The database.query() method iterates through selectionArgs for every ? it finds in selection. So, the array size should match the number of ? placeholders you're using in selection. (If there are more ? than selectionArgs values, then I believe nullgets substituted instead. I haven't verified this though.)

So basically, since it's possible to have multiple WHERE values substituted into selection, that's why selectionArgs is an array instead of a simple String.

Upvotes: 1

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