I want to save text file in sqlite android but it is giving an error android.database.sqlite.SQLiteConstraintException: NOT NULL constraint failed: at line long result = db.insert(TABLE_NAME,null,cv);.

@Override
public void onCreate(SQLiteDatabase db) {
    String create_table = "CREATE TABLE "   TABLE_NAME   "( "
              "ID INTEGER PRIMARY KEY ,"
              POSITION   " TEXT NOT NULL, "
              TXT_FILE   " BLOB NOT NULL, "
              _ID   " TEXT NOT NULL)";


    db.execSQL(create_table);

}

 public boolean add_txt_file(String id, byte[] txt_file) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();
        cv.put(_ID,id);
        cv.put(TXT_FILE,txt_file);
        long result = db.insert(TABLE_NAME,null,cv);
        if (result == -1){
            return false;
        } else {
            return true;
        }
    }

if (data != null) {
     Uri uri = data.getData();
     String path = uri.getPath();
     path = path.substring(path.indexOf(":")   1);
     Log.e("TAG", "readFile(path) "   Arrays.toString(readFile(path)));
     boolean save_txt_file = db.add_txt_file(id,
                       readFile(path));
     if (save_txt_file){
         Toast.makeText(this, "saved successfully", Toast.LENGTH_SHORT).show();
     } else {
         Toast.makeText(this, "failed", Toast.LENGTH_SHORT).show();
                                }

private byte[] readFile(String file) {
    ByteArrayOutputStream bos = null;
    try {
        File f = new File(Environment.getExternalStorageDirectory(),file);
        FileInputStream fis = new FileInputStream(f);
        byte[] buffer = new byte[1024];
        bos = new ByteArrayOutputStream();
        for (int len; (len = fis.read(buffer)) != -1;) {
            bos.write(buffer, 0, len);
        }
    } catch (FileNotFoundException e) {
        Log.e("TAG","error "   e.getMessage());
    } catch (IOException e2) {
        System.err.println(e2.getMessage());
    }
    return bos != null ? bos.toByteArray() : null;
}

The path gives this in log Download/Link_on.txt and the readFile(path) returns [49, 10, 48, 48, 58, 48...... but it is still failing to save the text file in db. Thanks for the help.

CodePudding user response：

In the CREATE statement of the table you have defined the column POSITION as NOT NULL, but in the method add_txt_file() you don't supply a value.

Add something like this line:

cv.put(POSITION, "some value");