I am using Cached updates in order to increase speed for my SQLites INSERT queries. The problem I am facing, is that inside the loop where I have my INSERT, I am using an auto-incemental value.
I am using TFDConnection and TFDQuery to implement my database writing part.
Before moving on the next Post() I need the value of the previous auto-incemental value. The problem is that auto-incremental value is not generated unless in call TFDquery.ApplyUpdates().
SO, is there a way that I can use CachedUpdates but also keep Auto-Incremental values that will be generated after calling TFDquery.ApplyUpdates()?
One idea that came up on my mind, is getting the last generated value with TFDConnection.GetLastAutoGenValue() and calculate how many row I will need. For example if I know that I will insert 5 rows and the last auto-generated value was 300, I know that my next values will be 301,302,303,304,305. The whole problem with this, is that I dont have control on which values correlate with the next Post().
Related
What I wanted is to display an alert when I move to the next row if the record that I inserted is already one of the records in the multi record block.
and in what trigger must I put it?
There are several options you can use.
One is to POST values entered (in WHEN-NEW-RECORD-INSTANCE) trigger. It will, well, post everything you entered so far. Then, you can write a WHEN-VALIDATE-ITEM trigger which SELECTs from that table and checks whether such a value already exists. Alternatively, if there's the UNIQUE CONSTRAINT on that (those) column(s), database will do its job itself, i.e. raise an exception.
Another option is to literally loop through all rows in a block and compare the first row's value with all the others, then the second row's values with all of them, etc.
Or, you can use a Record Group (usually used for Lists of Values). Basically, you'd check whether value you entered exists in a record group. More info, along with a FMB file, on Craig's blog.
Or, you can use calculated items, as described enter link description here (FMB attached as well).
As you can see, quite a few ways to do that; explore each of them and pick the one you find the most useful / attractive / easy to implement.
I'm using the new gcloud-java API (https://github.com/GoogleCloudPlatform/gcloud-java/tree/master/gcloud-java-datastore/src/main/java/com/google/cloud/datastore) for working with the Cloud Datastore. My specific question is on using GQL for pagination with cursors. I was able to page through the results one page at a time in the forward direction using cursors, but not having any luck with paging backwards.
Example Scenario:
Let's say I've 20 entities in a Kind with IDs 1 through 20. I have a page size of 5. Once I'm on the 3rd page (IDs 11 through 15), if I need to go one page back; i.e. retrieve IDs 6 through 10, what would be the correct GQL/sample code? Again, I prefer not to use offset with a number, but would like to use Cursors.
From what I can tell (actually tested), it looks like one needs to keep track of Start/End cursors for each page as they navigate in the forward direction, then use the saved cursors when there is a need to go back. I just want to make sure if this is the correct/only way or there is a simpler way to accomplish this.
Thanks in advance for your help.
If you add to your original query a sort by key (appended to the end of your "order by" clause), you should be able to reverse each property's sort order and use the latest cursor from your original query to get results in reverse.
Suppose you've iterated through some of the values from your forward query's QueryResults. You can call QueryResults's cursorAfter() method, which will return a cursor pointing right after the last result you saw from your original query. Now you can issue a new query (with the opposite sort order on each property, including the key property) using that cursor as the start cursor. You'll probably want to skip the first result, since it will be the last result you saw from the original query.
I try to add a new calculated column to sharepoint list that will show elapsed day. I enter name and write a formula like;
=ABS(ROUND(Today-Created;0))
The data type returned from this formula is: Single line of text
When I want to save I get an error like
Calculated columns cannot contain volatile functions like Today and
Me.
Calculated Column Values Only Recalculate As Needed
The values in SharePoint columns--even in calculated columns--are stored in SharePoint's underlying SQL Server database.
The calculations in calculated columns are not performed upon page load; rather, they are recalculated only whenever an item is changed (in which case the formula is recalculated just for that specific item), or whenever the column formula is changed (in which case the formula is recalculated for all items).
(As a side note, this is the reason why in SharePoint 2010 you cannot create or change a calculated column on a list that has more than the list view threshold of 5000 items; it would require a mass update of values in all those items, which could impact database performance.)
Thus, in order for calculated columns to accurately store "volatile" values like "Me" and "Today", SharePoint would need to somehow constantly recalculate those column values and continuously update the column values in the database. This simply isn't possible.
Alternatives to Calculated Columns
I suggest taking a different approach entirely instead of using a calculated column for this purpose.
Conditional Formatting: You can apply conditional formatting to highlight records that meet certain criteria. This can be done using SharePoint Designer or HTML/JavaScript.
Filtered List views: Since views of lists are queried and generated in real time, you can use volatile values in list view filters. You can set up a list view web part that only shows items where Created is equal to [Today]. Since you can place multiple list view web parts on one page, you could have one section for today's items, and another web part for all the other items, giving you a visual separation.
A workflow, timer job, or scheduled task: You can use a repeating process to set the value of a normal (non-calculated) column on a daily basis. You need to be careful with this approach to ensure good performance; you wouldn't want it to query for and update every item in the list if the list has surpassed the list view threshold, for example.
I found some conversations about this issue. Many people suggest to creating a new Date Time column, visible is false, default value is Today's Date and it will be named as Today. Then we can use this column in our formulas.
I tried this suggestion and yes error is gone and formula is accepted but calculated columns' values are wrong. I setted column Today is visible and checked, it was empty. Default value Today's Date was not working. When I looking for a solution for this issue I deleted column Today carelessly. Then I realized calculated columns' values are right.
Finally; I don't know what is trick but before using Today keyword in your formulas if you create a column named as Today and after your formula saving if you delete Today column, it is working.
UPDATE
After #Thriggle's answer I realized this approach doesn't work like a charm. Yes, formula doesn't cause an error when calculated column saving but it works correctly only first time, in the next day the calculated column shows old values, because its values are static as Thriggle explained.
I need a trigger to log updates on a table. As I want to log it I need to know the name of the updated column(s) in the trigger body. We have NEW and OLD but it doesn't tell me which column were updated.
If nothing else, I still have the choice between these two ugly solutions:
use one IF NEW.val <> OLD.val per column
use one trigger per column
PS: I saw this "COLUMNS_UPDATED" in SQL which represents what I am looking for.
In a specific table I have a SortOrder integer field that tells my page in which order to display the data. There are sets of data in the this field (based on a CategoryID field), and each set will have its own ordering. Users can add/remove/update records in this table.
My question is what is the best way to manage this SortOrder field? I would like to "reseed" it everytime a record is deleted or updated. Is this something I should be using a trigger for? Or should my code handle it and manage the reseeding?
What I used to do is use only odd numbers in the SortOrder field so upon changing the order, I would add or subtract 3 from the current value of the modified item and then do a reseed (order the items again using odd number indexes). Also I used to reseed after every insert or delete.
All you really have to worry about is swapping any two fields. All new entries go to the end and i'm sure you've got a mechanism by which the user can change the order. The order change, move up or down, really is a swap with a neighboring field. All you really care about is that all the fields are sorted properly. Don't let a mathematical sense of aesthetic drive you into creating something overly complex. (You'll end up with holes in your sequence after deletes are made but that's OK. It's an internal sequence marker used for ORDER BY. the numbers don't need to be made contiguous.)