在Android中的SQLite中删除具有多个条件的字符串行的最佳方法

Question

I have a database and in one of its tables i am storing paths to documents. Time from time i need to delete rows with specific extensions. I have an array with extensions and i am deleting rows from my db in this way

public void deletePathsExceptThis(String [] extensions){
    SQLiteDatabase db = getWritableDatabase();
    String query = "";
    for (int i=0; i< extensions.length-1; i++){
        query = query.concat(" LOWER(" + ALL_DOCUMENTS_PATH + ") NOT LIKE ('");
        query = query.concat(extensions[i]);
        query = query.concat("') OR ");
    }
    query = query.concat(" LOWER(" + ALL_DOCUMENTS_PATH + ") NOT LIKE ('");
    query = query.concat(extensions[extensions.length-1]) ;
    query = query.concat("')");
    db.delete(TABLE_ALL_DOCUMENTS, query, null);
}

But i am wondering, may be there are some more fast, productive or elegant ways to do that job? Thanks

Answer 1

you could try to use near the same GLOB word

https://www.sqlite.org/lang_expr.html#glob

but this yeilds near the same result.

Or write your own regexp method.

https://www.sqlite.org/lang_expr.html#regexp

but nevertheless I have to optimize your code:

public void deletePathsExceptThis(String [] extensions){
    if  (extensions == null || extensions.length == 0)
            return;
    SQLiteDatabase db = getWritableDatabase();
    StringBuilder query = new StringBuilder();
    for (int i = 0; i < extensions.length; i++){
       query.concat(" LOWER(").append(ALL_DOCUMENTS_PATH).append(") NOT LIKE ('");
       query.append(extensions[i].replaceAll("'","''"));
        String ext = i == extensions.length - 1 ? "" : " OR ";
       query.append("')").append(ext);
    }
    db.delete(TABLE_ALL_DOCUMENTS, query.toString(), null);
}