Question

I’m a noob when it comes to sqlite and not quite sure how to do this.

I want a database with a bunch of row, containing one word each. When the user types a word, I will validate it by checking if its in the database.

Things I dont have, I guess, and don’t know how to create, is an index? How do I insert that? How do I write the query to take advantage of index?

I also have two columns in there, “id and word”. Is it good to have the id or does it just take up space?

This is what I got so far:

CREATE TABLE words (id INTEGER PRIMARY KEY, word VARCHAR(15));

I don’t want words longer then 15 characters, so I set the VARCHAR(15);

INSERT INTO words(word) VALUES('hello');
INSERT INTO words(word) VALUES('bye');
etc. for all words

And to check a word:

NSString *sql = [NSString stringWithFormat:@"SELECT EXISTS(SELECT 1 FROM words WHERE word=\"%@\" LIMIT 1)", word];
const char *sqlStatement = [sql UTF8String];

if (sqlite3_prepare_v2(db, sqlStatement, -1, &selectStmt, NULL) == SQLITE_OK)
{
    int count = 0; 
    while(sqlite3_step(selectStmt) == SQLITE_ROW)
    {
        count = sqlite3_column_int(selectStmt, 0);
    }

    NSLog(@"COUNT: %i",count);

    //If count is 1, we have a match.  
}

Answer 1

Yes. Your Statement is ok.

You can also use ' intead of ":

NSString *sql = [NSString stringWithFormat:@"SELECT EXISTS(SELECT 1 FROM words WHERE word='%@' LIMIT 1)", word];

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Is it good to have the id or does it just take up space?

It depends on your need, I will suggest you should keep an Id field as primary key.

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For creating index you can use:

CREATE INDEX yourIndexName ON yourTableName ( yourColumnName )

For more about indexing check sqlite