SQLite - Is it possible to insert a BLOB via insert statement?

问题

I'm developing an Android application and i'm using a Sqlite database to store some bitmaps. I want some images to be automatically inserted when the user installs the application.

I'm using the SQLiteOpenHelper class like this:

public class DatabaseHelper extends SQLiteOpenHelper {

...

DatabaseHelper(Context context, String nameOfDB, int version, String[] scriptSQLCreate,
        String scriptSQLDelete) {
    super(context, nameOfDB, null, version);

    this.scriptSQLCreate = scriptSQLCreate;
    this.scriptSQLDelete = scriptSQLDelete;
}

@Override
public void onCreate(SQLiteDatabase db) {
    int numScripts = scriptSQLCreate.length;
    for(int i = 0; i<numScripts; i++){
    Log.i(TAG,"Creating database, executing script " + i);
    db.execSQL(scriptSQLCreate[i]);
    }
}
}

...

I want to pass a constant to the scriptSQLCreate parameter shown above that would be like so:

private static final String[] SCRIPT_DATABASE_CREATE = {
   "create table memes(  id integer primary key autoincrement," + 
                     + " img blob not null," + 
                     + " name text not null unique)" ,
   "insert into memes(img,name) values(BITMAP1,'1.jpg')",
   "insert into memes(img,name) values(BITMAP2,'2.jpg')",
   "insert into memes(img,name) values(BITMAP3,'3.jpg')"}    

}

Any help will be much apreciated,

Thx, Tulio Zahn

回答1:

If you really, really want to you can use a very long hex literal as a blob literal:

insert into memes(img, name) values(X'0102030405060708090a0b0c0d0e0f', '1.jpg')

However, this is usually a bad idea; instead, go look at parameterised queries. They will let you compile a statement once using placeholders instead of actual values, and then reuse it many times, filling in the placeholders as needed:

SQLiteStatement p = sqlite.compileStatement("insert into memes(img, name) values(?, ?)");

byte[] data = loadData("1.jpg");
p.bindBlob(1, data);
p.bindString(2, "1.jpg");
p.execute();

byte[] data = loadData("2.jpg");
p.bindBlob(1, data);
p.bindString(2, "2.jpg");
p.execute();

(Warning --- code not tested.)

In general you should be using parameterised queries everywhere, as they're a sure-fire way to avoid SQL injection attacks, plus are usually easier and clearer. Assembling SQL queries by glueing strings together should be avoided at all costs.

回答2:

Your data table has some invisible word which you can not see. Check your db file with the db tools like navicat for sqlite. Please pay attention to the error word in the table.

来源：https://stackoverflow.com/questions/8884058/sqlite-is-it-possible-to-insert-a-blob-via-insert-statement

标签

android

database

sqlite

bitmap

blob