I want to know if there is option to add in creation table automatic attribute or something like this that will save the create date of each "row" in table . I search on amazon documentation and didn't found something like this , I am new with dynamoDB ,and I do not have a lot of knowledge..
So , It's possible ?
Another issue - I want delete items (use on DeleteItemRequest) by filter on the date attribute - it's possible ?
It is not possible to add an attribute on each item automatically. What we do is for each element we want to have this we add a String called createdTime and populate it with a UTC milliseconds string.
When you delete you must have a full primary key (hash / hash+range) of the item you wish to delete. So in order to do that you either Query or Scan with a filter, to get the items you want to delete, and then run a delete item request (or batch) on them to remove them.
Related
I have a multi-select widget bound to a table that only contains relations. I want to use the related values for each record to populate the multi-select name.
Parent-Table
- Child-Table-One
- Child-Table-Two
No matter which way I try using the multi-select name paths, only the first record name in the multi-select gets populated with the related value from the related child table, the others just display the record ID of the Parent Table.
Do I need to use a function somehow to iterate through all records to get the related values for every record?
Binding to the Relation should get you a list of records. Assuming you're trying to get list of the display names, this should work:
(#datasource.item.Child1).concat(Array.from(#datasource.item.Child2))
I have a form that submits parameters to a query, then opens the resulting record in another form. The problem is, whenever there is more than one record it automatically puts the first one into the from without any kind of option to choose the record I want. I have a macro set up on the search button on the first form that submits the parameters to the query and then displays it in the second form, I've tried to set up another macro in between the two, but I don't know if it's possible to set up the expression creator to check the number of rows resulting from a query. Is it possible to modify the query to create a prompt to choose which record I want? Or should I change something else?
This is the query:(automatically created by access)
SELECT CHILD.CHILD_L_NAME, CHILD.CHILD_F_NAME, CHILD.DOB, CHILD.GENDER, CHILD.DAYS_IN_CARE,
CHILD.HOURS_PER_DAY, CHILD.ENROLLMENT_DATE, CHILD.CHILD_ADDRESS, CHILD.CHILD_CITY,
CHILD.CHILD_ZIP, CHILD.CHILD_STATE, CHILD.CLASSROOM, CHILD.SNACK, CHILD.LAST_UPDATED, CHILD.CIN
FROM CHILD
WHERE (((CHILD.CHILD_L_NAME)=[Forms]![Search]![L_NAME]) AND
((CHILD.CHILD_F_NAME)=[Forms]![Search]![F_NAME])) OR
(((CHILD.CHILD_L_NAME)=[Forms]![Search]![L_NAME]) AND
((CHILD.DOB)=[Forms]![Search]![DOB])) OR
(((CHILD.DOB)=[Forms]![Search]![DOB])) OR
(((CHILD.CHILD_L_NAME)=[Forms]![Search]![L_NAME]));
If I understood well your problem and you use VBA it's quite easy to do.
You can create a reduced query based on the query you're creating with the button. This new query should include all and only the fields that allows you to discriminate beetwen the records to show in the 2nd form.
For instance it could include LastName, FirstName and classroom to select between children with same full name.
You can count the number of records of this 2nd query and if greater than 1 it means that you have more than one children to show.
So you can use this 2nd query to populate a combo-box or a listbox for selecting the record you really want to show.
When number of records is 1 you can simply skip the listbox population using an if statement on recordcount.
Next step is opening the form with the selected (or unique) record.
Bye
I am trying to create a report putting a field called contact which has the name of a person. This name is linked directly to another table where I keep all the contacts.
For some strange reason, when I include this name (which in query view displays as the name of the contact), instead of the name appearing, the unique ID number is shown on my report.
As mentioned in the article cited in the above comment, you can use a Combo Box control on your report to do the lookup for you. To see how this can be done, create a new report based on the table containing the lookup field, then drag and drop that field onto the report. That will create a Combo Box control with properties that look something like this:
Row Source: SELECT [Clients].[ID], [Clients].[LastName] FROM Clients;
Bound Column: 1
Column Count: 2
Column Widths: 0";1"
You could use a similar Combo Box control on your actual report to display the client's name rather than their numeric ID value.
Another alternative would be to change the Control Source of the report's Text Box control to have it do a DLookUp() on the table. If the lookup field is named [client] then changing the Control Source of the Text Box to something like
=DLookUp("LastName","Clients","ID=" & [client])
would also work.
I wanted to add to the great answer by Gord:
When using a "web" database (started in Access 2007 I think), you cannot change a report's fields to ComboBox style, nor can you use DLookUp(). (web databases lack a ton of features)
The workaround for this, if you want to create a Web-Report that uses lookup fields, is to create a Web-Query first based on your Web-Table (all the Web-* stuff has a www planet icon over the logo, if you create a new Web-DB in Access 2007+ you'll see what I mean)
So, instead of Table -> Report, you'll have to do W-Table -> W-Query -> W-Report.
Then, the only thing you need to customize to get the data right is the W-Query. Start by trying to reproduce the look in the query to match what you want users to see in the report. Note that here in the query, lookups will work fine (instead of the unique ID's, you get field names like you want). However, this will not carry over to the report. To do that, you gotta get the actual text field name you want into the query:
You should already have one table in your query; start by adding the table that your first lookup field points to. For example, the table I want to print is called Stock_Boards, and it has a lookup field called PCBID_lookup that points to the table Stock_PCBs.
Since you're using lookup fields, there should already be a relationship line between the two tables when you add the second one. If there isn't, something has gone horribly wrong.
Now, see how that line connects two fields on the two different tables? For example, I've got my PCBID_lookup field on my Stock_Boards table, which connects to the ID field on my Stock_PCBs table. If I created a report from this now, PCBID_lookup would be a number, a number that correlates to the ID of a record on Stock_PCBs.
To fix it, I will add the name field I want to show up on the report. In my example, that happens to be a Part Number, rather than the ID. I add the PartNumber field from my Stock_PCBs table to the query, and remove the PCBID_lookup field of the Stock_Boards table from my query.
Since PartNumber is what I want to show up on my report, it effectively replaces the original field (PCBID_lookup)
Repeat for all lookup fields you want in your report.
I had 1 more: I removed the Status field of the Stock_Boards table (which was an ID/Lookup) and added the 'Status' field from the Status table (which was the actual text name)
When finished, your query should look exactly how you want the data to appear, without any special tricks or asking Access to do something unnatural. Save your query, and create a web-report from it. Done!
I have a list of values in a SQL Table which are used to popluate a DropDownList, having a unique Integer as the value of each item and a String as the visible text (via SqlDataSource). There is also a third field in the database which is a flag to indicate whether the list item is active or not (inactive items are not shown in the DropDownList)
Selections made in the dropdown are stored in the database as their integer value (as part of a dataset making up the overall record), not the text value.
Over time, the items in the DropDownList may be removed by marking the items as inactive. However, there is still a need to open old records which may have had a now-inactive item as part of it's data...
My question is, what's the best way to ensure that the missing value included in the dropdown for the old record?
The two methods that spring to mind are to either:
Populate DropDownList with only the currently active items and, when loading a record, catch when the app tries to select a value that doesn't exist, go back to the db to see what it should be (the text value) and manually add it into the dropdown.
or...
Populate DropDownList with all list items (both active and inactive), load the record and then programatically remove all the inactive items (execpt for any that are now selected).
Neither of these seem particularly efficient, so I was wondering whether there is a best practice for this kind of thing?
there are so many optimum ways to do that sort of things, i am defining here a couple of them, use any of following if your Drop down list items count is less than 200 , lets say drop down list is of Products
1)
i) Load all Products records in drop down list and hide the inactive ones by setting visible=false
i) When you load a user record than look for its drop down list value if its visible than select it and enjoy, if its not visible than make it visible by setting its property visible=true and select it and also set its index or id in a flag to change its visibility(visible=false) again after your/users required operation performed.
2)
i) load only active Product records in drop down list ii) while loading a user record also load its product details(name, id, inactive_status) using Joins in sql.
iii) check in that user record if item is inactive then add its record in drop down list as you have all its details now with user details record else just select it.
IMPORTANT NOTE: if you drop down list has items in millions than use ADVANCE SEARCH techniques
The first thing I would do is question your business logic - should you be able to make an item inactive if it is being used as a foreign key in an active row elsewhere? If you make it inactive should it not remove all foreign keys as well?
To answer your question though I would go with a variation on the second idea but filtering in the page like that is probably slower than doing directly with SQL so I guess you have something like this at the moment to populate the dropdown
SELECT * FROM Table WHERE Active = 1
You should already have your record and the foreign key value so I would change it to this
SELECT * FROM Table WHERE Active = 1 OR PrimaryKey = [YourForeignKey]
Then you will always have the selected item but should also be fairly efficient.
I have a table that contains three columns.
"UserId" type-nvarchar
"PostAuthorId" type-nvarchar
"Post" type-text
This table will contain "wall" posts like in facebook for each user's page. I am going to use a gridview on each user's page to display the posts. The issue is I want to display them with the latest(most current) post being first and the earliest post being last.
I have never used autoincrement before and I am not sure if that is the answer. If it is, I do not know how to use it. I thought about adding a date posted column and then ordering by date.
If I end up using the date column, I could also display the date on the post. Is there a way to convert the date to a readable format?
What is the best way of implementing this type of ordering?
If you use AutoIcrement the first record will start with 1 and each record will increment from there. (default setting)
If you want to sort them by newest first do an ORDER BY ID DESC
I would suggest making a column called wallPostID then setting that to AutoIncrement and also your Primary Key
Date Formating:
If you are displaying this data in a gridView
Go to Edit Columns on your grid view
CLick on the Date field under "Selected Fields" on the bottom left
Under "BoundField properties" on the right Go to Data -> DataFormatString
{0:d} will display as 1/1/2010
This site has more info in string formatting
http://msdn.microsoft.com/en-us/library/fht0f5be.aspx
A datetime column would definitely work for something like this. Assuming you are using MS-SQL, you can also attach a default value to the column using a built-in function like GETDATE(). That way, you only have to input the data that matters and the database will take care of adding the datetime column.
For converting a datetime to a readable format try:
DateTime postDate;
string value = postDate.ToShortDateString();
You should always use an ID field that auto increments. Can also be used as your PK
I would suggest the DateTime field rather than the autoincrement simply because it will not only serve as an effective Sort field, it also preserves information that you may well want to display. If you want the most recent first you'll sort using the Date and a "DESC" modifier:
Select ... Order By [Date] DESC;
When you retrieve the data, you can retrieve it as a DateTime and modify it using C#. You can use "ToShortDateString()" as suggested by mdresser if you just wish to show the date or ToString("...") if you wish to show the time as well. You can also use SQL to convert it into a string before retrieving it:
convert(Varchar(10), #mydatetime, 101)
If you look in MSDN you'll see the various conversion codes (101 is the code used above) that can be used to translate the date in various ways.
UPDATE: You may want to use an autoincrementing field for your application for reasons other than your expressed need to sort wall entries. They are easy to use - just mark the field as an Identity if using SQL Server (other DBs are similar). As far as using them in your program, just think of the field as an Int field that you never have to set.
Now, why would you use a auto-incrementing field? Perhaps the most straightforward reason is so that they give you have an easy way to identify each record. For example, if you permit people to alter or delete their wall entries, the auto-incrementing field is ideal as it gives you a way to easily look up each record (each record will be assigned its own, unique value). You might put an "x" next to the record like StackOverflow does and make it a call back with the UID (auto-increment) value. Note that you should set up your primary key on the UID field if you'll be doing this.
Now, if you find them useful for this reason then you could also sort by the UID. I would still store the date so that you can provide Date and Time feedback as to when an entry was made on the wall but this would no longer be your indexed or sorted field.