How to retrieve the data using query statement in Swift?

Question

I want to retrieve the data from my table named cache_image, but I am not sure how to do that and I am facing an error here.

func checkCachedImages() ->Bool{
    database?.open()
    var count = Int()
    for i in images{
        do{
            if let value = database?.executeQuery("SELECT DOWNLOAD_URL FROM CACHED_IMAGE WHERE IMAGE_NAME = ?", withArgumentsIn: [i]){
                while value.next(){
                    print(value.string(forColumn: "IMAGE_NAME"))
                    print(value.string(forColumn: "DOWNLOAD_URL"))
                    count += 1
                    print(count)
                }
            }
        }catch {
            print(error)
        }
    }
    database?.close()
    if count == images.count{
        print("The count is \(count)")
        return true
    }

    return false
}

I do have a table named cached_image and two columns named image_name and download_url but when i try to access that using

print(value.string(forColumn: "IMAGE_NAME")

it is displaying warning :

Couldn't find image_name and for column "download_url", it is showing "Optional("")"

Please help me to solve this issue.

why do you use the "DOWNLOAD_URL" and "IMAGE_NAME" in uppercase — Quoc Nguyen
– Quoc Nguyen, Commented Sep 18, 2018 at 9:27
I don't know because in query statement it was uppercased, so i used so — sathish kumar
– sathish kumar, Commented Sep 18, 2018 at 9:30
can you try to change the table name and columns name to lowercase — Quoc Nguyen
– Quoc Nguyen, Commented Sep 18, 2018 at 9:31
in the example of fmdb, they wrote try db.executeUpdate("INSERT INTO foo (bar) VALUES (?)", values: [1])", did you double check your querry type, like (?), not ?, withArgumentsIn and values — Quoc Nguyen
– Quoc Nguyen, Commented Sep 18, 2018 at 9:40

Joakim Danielson · Accepted Answer · 2018-09-18 10:54:53Z

2

You can't read image_name from the result since it isn't part of the SELECT clause but you don't need it since you can get it from i

var numberOfRows = 0
var urls: [String] = ()
print("Image name: \(i)")
if let result = try database?.executeQuery("SELECT download_url FROM CACHED_IMAGE WHERE IMAGE_NAME = ?", values: [i]) {
    while result.next() {
        numberOfRows += 1
        let url = result.stringForColumnIndex(0)
        urls.append(url)
        print("\(url), \(i)")
    }
}
print(numberOfRows)

edited Sep 18, 2018 at 10:54

answered Sep 18, 2018 at 10:23

Joakim Danielson

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10 Comments

sathish kumar Over a year ago

Hello @Joakim Danielson I tried the above solution , but the print(result.intForColumnIndex(0)) produces 0

Joakim Danielson Over a year ago

I don't know where you did that print

sathish kumar Over a year ago

I want to print download_url, how to get that?

Joakim Danielson Over a year ago

I do that, it is in the url variable. just modify my print statement.

sathish kumar Over a year ago

Let us continue this discussion in chat.

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