Retrieve data from sqlite net with parameters and blob

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Asked 5 years, 8 months ago

Modified 5 years, 8 months ago

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I'm using sqlite-net and sqlite-net-extensions for the blob in a Xamarin.Android project. I have this schema:

    public enum TemplateCategories
    {
        Emojis,
        Stars,
        Hearts,
        Characters,
        Emotions,
    }

public class Templates
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }
    public int Category { get; set; }
    [TextBlob("imagesBlobbed")]
    public List<int> Images { get; set; }
    public string imagesBlobbed { get; set; }
}

and i'm trying to add a Templates object with this:

    public static void CreateDB(SQLiteConnection db)
    {
        db.CreateTable<Templates>();
        AddTemplate(
            db,
            (int)TemplateCategories.Emojis,
            new List<int>
            {
            Resource.Drawable.ic_angry,
            Resource.Drawable.ic_sad,
            Resource.Drawable.ic_neutral,
            Resource.Drawable.ic_happy,
            Resource.Drawable.ic_smiling,
            }
        );

    public static void AddTemplate(SQLiteConnection db, int category, List<int> images)
    {
        var alreadyExist = db.Table<Templates>().Where(record => record.Images == images);

        if (alreadyExist?.Count() == 0)
        {
            var template = new Templates()
            {
                Category = category,
                Images = images,
            };
            db.InsertWithChildren(template, recursive: true);
        }
    }

but at AddTemplate im getting null reference exception in line var alreadyExist . I have look the documentation and i'm not sure how i can search for a specific item (List blob in my case) and retrieve it.

I just want to be sure first that the data that im inserting are not already in the DB.

Is my approach wrong? Since i want to be able to query the List Images should i create an OneToMany relationship with another table that will hold the Images instead of a blob?

Exception:

**System.NullReferenceException:** 'Object reference not set to an instance of an object.'

03-08 00:38:28.681 D/Mono    (20388): DllImport attempting to load: '/system/lib/liblog.so'.
03-08 00:38:28.682 D/Mono    (20388): DllImport loaded library '/system/lib/liblog.so'.
03-08 00:38:28.682 D/Mono    (20388): DllImport searching in: '/system/lib/liblog.so' ('/system/lib/liblog.so').
03-08 00:38:28.682 D/Mono    (20388): Searching for '__android_log_print'.
03-08 00:38:28.682 D/Mono    (20388): Probing '__android_log_print'.
03-08 00:38:28.682 D/Mono    (20388): Found as '__android_log_print'.
03-08 00:38:28.686 I/MonoDroid(20388): UNHANDLED EXCEPTION:
03-08 00:38:28.690 I/MonoDroid(20388): System.NullReferenceException: Object reference not set to an instance of an object.
03-08 00:38:28.690 I/MonoDroid(20388):   at SQLite.TableQuery`1[T].CompileExpr (System.Linq.Expressions.Expression expr, System.Collections.Generic.List`1[T] queryArgs) [0x008b5] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.690 I/MonoDroid(20388):   at SQLite.TableQuery`1[T].CompileExpr (System.Linq.Expressions.Expression expr, System.Collections.Generic.List`1[T] queryArgs) [0x0009d] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.690 I/MonoDroid(20388):   at SQLite.TableQuery`1[T].GenerateCommand (System.String selectionList) [0x0005f] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.690 I/MonoDroid(20388):   at SQLite.TableQuery`1[T].Count () [0x00000] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.690 I/MonoDroid(20388):   at RateMe.Helpers.TemplateDB.AddTemplate (SQLite.SQLiteConnection db, System.Int32 category, System.Collections.Generic.List`1[T] images) [0x00077] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\Helpers\TemplateDB.cs:25 
03-08 00:38:28.690 I/MonoDroid(20388):   at RateMe.Helpers.TemplateDB.CreateDB (SQLite.SQLiteConnection db) [0x00009] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\Helpers\TemplateDB.cs:68 
03-08 00:38:28.690 I/MonoDroid(20388):   at RateMe.MainApplication.GetTemplateById (System.Int32 id) [0x00025] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\MainApplication.cs:43 
03-08 00:38:28.690 I/MonoDroid(20388):   at RateMe.MainActivity.SetButtonImages () [0x0008c] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\MainActivity.cs:554 
03-08 00:38:28.690 I/MonoDroid(20388):   at RateMe.MainActivity.OnResume () [0x0000f] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\MainActivity.cs:507 
03-08 00:38:28.690 I/MonoDroid(20388):   at Android.App.Activity.n_OnResume (System.IntPtr jnienv, System.IntPtr native__this) [0x00009] in <985f5179c1dd4b3b98fb1b8dcc1ee9be>:0 
03-08 00:38:28.690 I/MonoDroid(20388):   at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.13(intptr,intptr)
03-08 00:38:28.707 E/AppCenterCrashes(20388): Unhandled Exception from source=AndroidEnvironment
03-08 00:38:28.707 E/AppCenterCrashes(20388): System.NullReferenceException: Object reference not set to an instance of an object.
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at SQLite.TableQuery`1[T].CompileExpr (System.Linq.Expressions.Expression expr, System.Collections.Generic.List`1[T] queryArgs) [0x008b5] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at SQLite.TableQuery`1[T].CompileExpr (System.Linq.Expressions.Expression expr, System.Collections.Generic.List`1[T] queryArgs) [0x0009d] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at SQLite.TableQuery`1[T].GenerateCommand (System.String selectionList) [0x0005f] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at SQLite.TableQuery`1[T].Count () [0x00000] in <84b9c9e630fa45bd8ac799333976ebbf>:0 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at RateMe.Helpers.TemplateDB.AddTemplate (SQLite.SQLiteConnection db, System.Int32 category, System.Collections.Generic.List`1[T] images) [0x00077] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\Helpers\TemplateDB.cs:25 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at RateMe.Helpers.TemplateDB.CreateDB (SQLite.SQLiteConnection db) [0x00009] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\Helpers\TemplateDB.cs:68 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at RateMe.MainApplication.GetTemplateById (System.Int32 id) [0x00025] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\MainApplication.cs:43 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at RateMe.MainActivity.SetButtonImages () [0x0008c] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\MainActivity.cs:554 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at RateMe.MainActivity.OnResume () [0x0000f] in C:\Users\Exoskeletor\Documents\Projects\RateMe\RateMe\MainActivity.cs:507 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at Android.App.Activity.n_OnResume (System.IntPtr jnienv, System.IntPtr native__this) [0x00009] in <985f5179c1dd4b3b98fb1b8dcc1ee9be>:0 
03-08 00:38:28.707 E/AppCenterCrashes(20388):   at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.13(intptr,intptr)
03-08 00:38:28.714 D/Mono    (20388): Loading reference 5 of /storage/emulated/0/Android/data/com.cdrosos.simplecustomerfeedback/files/.__override__/Microsoft.AppCenter.Crashes.dll asmctx DEFAULT, looking for System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e
03-08 00:38:28.714 D/Mono    (20388): Assembly Ref addref Microsoft.AppCenter.Crashes[0x9d908ac0] -> System.Core[0x872b3280]: 8
03-08 00:38:28.744 D/Mono    (20388): DllImport searching in: '__Internal' ('(null)').
03-08 00:38:28.744 D/Mono    (20388): Searching for 'java_interop_jnienv_new_local_ref'.
03-08 00:38:28.744 D/Mono    (20388): Probing 'java_interop_jnienv_new_local_ref'.
03-08 00:38:28.744 D/Mono    (20388): Found as 'java_interop_jnienv_new_local_ref'.
03-08 00:38:28.782 W/zygote  (20388): JNI RegisterNativeMethods: attempt to register 0 native methods for android.runtime.JavaProxyThrowable
03-08 00:38:28.786 D/Mono    (20388): DllImport searching in: '__Internal' ('(null)').
03-08 00:38:28.786 D/Mono    (20388): Searching for 'java_interop_jnienv_throw'.
03-08 00:38:28.786 D/Mono    (20388): Probing 'java_interop_jnienv_throw'.
03-08 00:38:28.786 D/Mono    (20388): Found as 'java_interop_jnienv_throw'.
**System.NullReferenceException:** 'Object reference not set to an instance of an object.'

03-08 00:38:30.941 E/mono-rt (20388): [ERROR] FATAL UNHANDLED EXCEPTION: System.NullReferenceException: Object reference not set to an instance of an object.
03-08 00:38:30.941 E/mono-rt (20388):   at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.13(intptr,intptr)
03-08 00:38:30.941 E/mono-rt (20388):   at (wrapper native-to-managed) Android.Runtime.DynamicMethodNameCounter.13(intptr,intptr)

edited Mar 7, 2020 at 22:39

asked Mar 7, 2020 at 18:27

CDrosos

2,5484 gold badges28 silver badges50 bronze badges

1

public List<int> Images { get; set; } = new List<int>();

Pethical
– Pethical

2020-03-07 22:25:57 +00:00
Commented Mar 7, 2020 at 22:25
1

thanks for the comment, i still see the null reference exception

CDrosos
– CDrosos

2020-03-07 22:39:49 +00:00
Commented Mar 7, 2020 at 22:39

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