Suppose I've the 'dom' table which contains two fields
code
name
Code should be primary key. In case if I enter values('SD', 'domnic')
then again if I enter ('SD', 'domnic1')
in asp.net I've wrote validation so i can receive alert message.
protected void ButtonSave_Click(object sender, EventArgs e)
{
try
{
if (Mode == "Add")
{
primarykeyValidation();-------------->validation
if (strpkval == TextBoxWorkshopid.Text)
{
Alert.Show("code Already Exists");
TextBoxWorkshopid.Text = string.Empty;
TextBoxWorkshopid.Focus();
return;
}
}
...
public void primarykeyValidation()
{
DataSet dspkval = new DataSet();
try
{
objaccess.Option = "P";
objaccess.code= TextBoxWorkshopid.Text;
dspkval = objaccess.retriveOutsideWorkshops();
if (dspkval != null && dspkval.Tables.Count != 0 && dspkval.Tables[0].Rows.Count != 0)
{
strpkval = dspkval.Tables[0].Rows[0]["CODE"].ToString();
}
}
catch (System.Exception ex)
{
throw ex;
}
}
In case I enter('sd','domnic') it won't show the message just error thrown due to violation of primary key.
In "P" option I've wrote query as
select code from xxx where code=#code
so if i enter small case'sd' then i sholud receive alert message that "code aleady exits but it wouldnt show the
message........
1) Configure your database for case sensitivity. Known as collation. It does affect the entire database, though.
2) You can force a given query to have specific collation: http://web.archive.org/web/20080811231016/http://sqlserver2000.databases.aspfaq.com:80/how-can-i-make-my-sql-queries-case-sensitive.html.
3) You could modify the business logic so that all PK values are made upper case before being sent to the database in the first place. You'd have to do this for updates/inserts as well as queries though, so it could get messy (and be careful that your queries are still sargable i.e. don't put UPPER(#code) in your queries - actually modify the value before putting it in the parameter).
Related
I am implementing a method using Vertx to check the existence of certain value in the database and use Handler with AsyncResult.
I would like to know which one is the best practice:
Option 1: When nothing found, Handler is with succeededFuture but with result as FALSE:
public void checkExistence (..., String itemToFind, Handler<AsyncResult<Boolean>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<JsonObject> results = queryHandler.result();
boolean foundIt = false;
for (JsonObject json: results) {
if (json.getString("someKey").equals(itemToFind)) {
foundIt = true;
break;
}
}
resultHandler.handle(Future.succeededFuture(foundIt));
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
Option 2: When nothing found, Handler is with failedFuture:
public void checkExistence (..., String itemToFind, Handler<AsyncResult<Void>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<JsonObject> results = queryHandler.result();
boolean foundIt = false;
for (JsonObject json: results) {
if (json.getString("someKey").equals(itemToFind)) {
foundIt = true;
break;
}
}
// HERE IS THE DIFFERENCE!!!
if (foundIt) {
resultHandler.handle(Future.succeededFuture());
} else {
resultHandler.handle(Future.failedFuture("Item " + itemToFind + " not found!"));
}
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
UPDATE:
Let's say I have another example, instead of checking the existence, I would like to get all the results. Do I check the Empty results? Do I treat Empty as failure or success?
Option 1: only output them when it's not null or empty, otherwise, fail it
public void getItems(..., String itemType, Handler<AsyncResult<List<Item>>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<Item> items = queryHandler.result();
if (items != null && !items.empty()) {
resultHandler.handle(Future.succeededFuture(items));
} else {
resultHandler.handle(Future.failedFuture("No items found!"));
}
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
Option 2: output results I got, even though it could be empty or null
public void getItems(..., String itemType, Handler<AsyncResult<List<Item>>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<Item> items = queryHandler.result();
resultHandler.handle(Future.succeededFuture(items));
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
The 1st one option is better, because you can clearly say, that checkExistence returned True or False and completed successfully or it failed with some exception (database issue, etc.).
But lets say, you've decided to stick with 2nd option. Then, imagine you have another method:
void getEntity(int id, Handler<AsyncResult<Entity>> resultHandler);
If entity with provided id doesn't exists, will you throw exception (using Future.failedFuture) or return null (using Future.succeededFuture)? I think, you should throw exception to make your methods logic similar to each other. But again, is that exceptional situation?
For case with returning list of entities you can just return empty list, if there are no entities. Same goes to single entity: it's better to return Optional<Entity> instead of Entity, because in this way you avoid NullPointerException and don't have nullable variables in the code. What's better: Optional<List<Entity>> or empty List<Entity>, it's open question.
Particularly if you're writing this as reusable code, then definitely go with your first option. This method is simply determining whether an item exists, and so should simply return whether it does or not. How is this particular method to know whether it's an error condition that the item doesn't exist?
Some caller might determine that it is indeed an error; it that's the case, then it will throw an appropriate exception if the Future returns with false. But another caller might simply need to know whether the item exists before proceeding; in that case, you'll find yourself using exception handling to compose your business logic.
I want to check my form before inserting to prevent insert duplicate ProductSerial in my data base.
so how can i check the txtProductSerial.text with my database and if it is duplicate I PREVENT INSERTION.
This are my codes
protected void fvwSoldForm_ItemInserting(object sender, FormViewInsertEventArgs e)
{
e.Values["DateX"] = DateTime.Now;
e.Values["IsDeleted"] = false;
e.Values["Confirmed"] = false;
var solded = db.SoldedByResellers.ToList();
solded = solded.Where(p => p.ProductSerial == NumericSerial.Text).ToList();
if (solded.Count > 0)
Alert("Please Change the serial code, This code Used before");
//Here WHAT EVER I DO THE INSERTING GOES ON. I WANT TO STOP INSERTING HERE
}
To cancel the operation, set:
e.Cancel = true;
This will prevent the insert from happening. See the MSDN documentation for an example.
Scenario:
User submits search criteria and selects an item from search results on the same page, which navigates to a new page of details for the selected item.
When the User returns to the search screen, the search criteria & results (including selected page and sort-order) should be preserved from their last visit.
Related information:
All form submissions are POSTs.
Navigation back to the search screen may not be available from last browser history (e.g. more than one details screen may be encountered, or the user may navigate directly to the search screen from an alternative menu.)
Search results are provided using Telerik RadGrid control.
I'm looking for a generic solution that will be able to be applied to different search screens.
In some instances, the item may be DELETED from within the details screen, and should therefore not appear in the search results when the screen is next encountered.
Thoughts:
I've read a lot of suggested methods for addressing various parts of this scenario, but I'm still confused; no comprehensively "correct" solution jumps to the forefront.
I guess I'm asking for recommendations/approach rather than a whole solution spelled out for me (although that would be nice! ;-)
The .NET VIEWSTATE would seem to do exactly what I'm after (with the exception of #5) - Is there some way of leveraging off this so that viewstate can be used between pages, and not just between postbacks to the same page? (e.g. can I store/restore viewstate to/from a session variable or something? I haven't seen this suggested anywhere and I'm wondering if there's a reason why.)
Thanks in advance.
Thanks for all the advice.
For the benefit of others, here is a solution to this issue (no doubt there's room for improvement, but this works satisfactorily for the moment).
4 functions...
StoreSearchCookie - Persist the state/values of a panel of search criteria and a results grid in a cookie with a specified UID.
RestoreSearchCookie_Criteria - Read the cookie and re-populate the search criteira
RestoreSearchCookie_Results - Read the cookie and restore the grid state.
FindFormControls - Helper method to recursively find form-input controls in a container (pinched & modified from elsewhere on Stack Overflow)
NB...
I haven't addressed the multiple-tabs issue because our application doesn't allow them anyway.
RestoreSearchResults utilises GridSettingsPersister.cs available from Telerik website, (but I had to modify it to store the page number as well)
Usage is as follows...
protected void Page_PreRender(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
// Store the state of the page
StoreSearchCookie("SomeSearchPage", pnlSearchCriteria, gridResults);
}
else
{
// Restore search criteria
RestoreSearchCookie_Criteria("SomeSearchPage");
// Re-invoke the search here
DoSearch(); // (for example)
// Restore the grid state
RestoreSearchCookie_Results("SomeSearchPage");
}
}
Code follows...
protected void StoreSearchCookie(string cookieName, Panel SearchPanel, RadGrid ResultsGrid)
{
try
{
HttpCookie cookieCriteria = new HttpCookie("StoredSearchCriteria_" + cookieName);
// 1. Store the search criteria
//
List<Control> controls = new List<Control>();
FindFormControls(controls, SearchPanel);
foreach (Control control in controls)
{
string id = control.ID;
string parentId = control.Parent.ID;
string uid = string.Format("{0}>{1}", parentId, id);
string value = "";
Type type = control.GetType();
bool isValidType = true; // Optimistic!
if (type == typeof(TextBox))
{
value = ((TextBox)control).Text;
}
else if (type == typeof(DropDownList))
{
value = ((DropDownList)control).SelectedValue;
}
else if (type == typeof(HiddenField))
{
value = ((HiddenField)control).Value;
}
else if (type == typeof(RadioButton))
{
value = ((RadioButton)control).Checked.ToString();
}
else if (type == typeof(CheckBox))
{
value = ((CheckBox)control).Checked.ToString();
}
else
{
isValidType = false;
}
if (isValidType)
{
cookieCriteria.Values[uid] = value;
}
}
cookieCriteria.Expires = DateTime.Now.AddDays(1d);
Response.Cookies.Add(cookieCriteria);
// 2. Persist the grid settings
//
GridSettingsPersister SavePersister = new GridSettingsPersister(ResultsGrid);
HttpCookie cookieResults = new HttpCookie("StoredSearchResults_" + cookieName);
cookieResults.Values["GridId"] = ResultsGrid.ID;
cookieResults.Values["GridSettings"] = SavePersister.SaveSettings();
cookieResults.Expires = DateTime.Now.AddDays(1d);
Response.Cookies.Add(cookieResults);
}
catch (Exception exception)
{
Logger.Write(exception);
}
}
protected void RestoreSearchCookie_Criteria(string cookieName)
{
try
{
HttpCookie cookieCriteria = Request.Cookies["StoredSearchCriteria_" + cookieName];
if (cookieCriteria != null)
{
foreach (string key in cookieCriteria.Values.AllKeys)
{
string value = cookieCriteria[key];
string[] ids = key.Split('>');
string parentId = ids[0];
string id = ids[1];
Control control = FindControl(parentId).FindControl(id);
Type type = control.GetType();
if (type == typeof(TextBox))
{
((TextBox)control).Text = value;
}
else if (type == typeof(DropDownList))
{
((DropDownList)control).SelectByValue(value);
}
else if (type == typeof(HiddenField))
{
((HiddenField)control).Value = value;
}
else if (type == typeof(RadioButton))
{
((RadioButton)control).Checked = Boolean.Parse(value);
}
else if (type == typeof(CheckBox))
{
((CheckBox)control).Checked = Boolean.Parse(value);
}
}
}
}
catch (Exception exception)
{
Logger.Write(exception);
}
}
protected void RestoreSearchCookie_Results(string cookieName)
{
try
{
HttpCookie cookieResults = Request.Cookies["StoredSearchResults_" + cookieName];
if (cookieResults != null)
{
string gridId = cookieResults.Values["GridId"];
string settings = cookieResults.Values["GridSettings"];
RadGrid grid = (RadGrid)FindControl(gridId);
GridSettingsPersister LoadPersister = new GridSettingsPersister(grid);
LoadPersister.LoadSettings(settings);
grid.Rebind();
}
}
catch (Exception exception)
{
Logger.Write(exception);
}
}
private void FindFormControls(List<Control> foundSofar, Control parent)
{
List<Type> types = new List<Type> { typeof(TextBox), typeof(DropDownList), typeof(RadioButton), typeof(CheckBox), typeof(HiddenField) };
foreach (Control control in parent.Controls)
{
if (types.Any(item => item == control.GetType()))
{
foundSofar.Add(control);
}
if (control.Controls.Count > 0)
{
this.FindFormControls(foundSofar, control); // Use recursion to find all descendants.
}
}
}
I have a web page that is pulling information about a specific database entry based on the reference number of that database entry. This reference number is not the SQL ID number, but a number that we assign at entry time.
This reference number is passed to the page in the form of a query string, and as long as the reference number actually exists in the database, everything is fine. However, if the reference number does not exist, my details page comes up blank: no exception or anything.
I'm not sure how relevant sharing my code is in this case, but I'll play it safe:
protected void Page_Load(object sender, EventArgs e)
{
using (KidsEntities detailEntities = new KidsEntities())
{
string imgPath = ConfigurationManager.AppSettings["imagePath"];
string KidNum = Request.QueryString["ChildNum"].ToString();
var KidSpecific = from Kid in detailEntities.Kids
where Kid.Number == KidNum
... ;
DescRepeater.DataSource = KidSpecific.ToList();
DescRepeater.DataBind();
}
}
I can put in a redirect in case some joker tries to bring up my details page without going through the main directory (which would bring up a null query string), but if used correctly, my query string will never be null or empty. What I'm trying to prepare for is if someone bookmarks my details page with a query string that was valid at the time of bookmarking, but then gets taken down.
How can I check to make sure there is a reference number in the database that matches the query string before the var "KidSpecific" fires? If there is no such reference number, I need to be able to use a Response.Redirect to put up an error page instead of the blank screen that shows now.
Thanks in advance for any help.
Why do you need to do your check before the query fires? You'll have to check the database for the entry either way. Try redirecting if your query comes up empty:
protected void Page_Load(object sender, EventArgs e)
{
using (KidsEntities detailEntities = new KidsEntities())
{
string imgPath = ConfigurationManager.AppSettings["imagePath"];
string KidNum = Request.QueryString["ChildNum"].ToString();
var KidSpecific = from Kid in detailEntities.Kids
where Kid.Number == KidNum
... ;
var KidSpecificList = KidSpecific.ToList();
//Redirect if there are no results!
if (KidSpecificList.Count() < 1)
Response.Redirect("RedirectPage.aspx");
DescRepeater.DataSource = KidSpecificList;
DescRepeater.DataBind();
}
}
You can check quety string with string.IsNullOrEmpty like this:
protected void Page_Load(object sender, EventArgs e)
{
using (KidsEntities detailEntities = new KidsEntities())
{
string imgPath = ConfigurationManager.AppSettings["imagePath"];
string KidNum = Request.QueryString["ChildNum"].ToString();
if ( string.IsNullOrEmpty ( KidNum ) ) {
Response.Redirect ( "WhatEverURI" );
} else {
var KidSpecific = from Kid in detailEntities.Kids
where Kid.Number == KidNum
... ;
DescRepeater.DataSource = KidSpecific.ToList();
DescRepeater.DataBind();
}
}
}
There must be a way to enable creation and insertion of a record from a AxGridView without using the Tunnel and Wizard approach. From what I have found on the Internet so far, the only example is using a Wizard, and I honestly don't find that to be a user friendly approach.
Has anyone tried to enable insertion of records directly from a AxGridView?
Yes it is possible to enter data through AxGridView. Just enable Editing, deleting for that control. And one more thing to make new row - you have to make addditional button - create new line, and code behind:
protected void NewLine_Click(object sender, EventArgs e)
{
int editIdx = AxGridView1.EditIndex;
try
{
// Save the last unsaved line if any
if (AxGridView1.EditIndex != -1 && AxGridView1.Rows.Count > 0)
{
this.AxGridView1.UpdateRow(AxGridView1.EditIndex, true);
}
DataSetViewRow dsvr = this.dsv.AddNew();
}
catch (System.Exception ex)
{
AxExceptionCategory exceptionCategory;
if (!AxControlExceptionHandler.TryHandleException(this, ex, out exceptionCategory))
{
// Throw the fatal exception
throw;
}
if (exceptionCategory == AxExceptionCategory.NonFatal)
{
AxGridView1.EditIndex = editIdx;
}
}
}
private DataSetView dsv //get dataset view
{
get
{
DataSet dataSet = this.AxDataSource1.GetDataSet();
return dataSet.DataSetViews[this.AxGridView1.DataMember];
}
}