I I'm busy with editing my stored procedures for Reports i created a while back.
I encountered a problem where the parameters being sent to the stored procedures comes in all kinds of funky formats from multiple computers.
Some of the formats i have encountered has been
'2017-01-31'
'2017-31-01'
'01-01-2017'
'31012017'
'20170131'
I desperately need a way to handle all these different formats.
the '31012017' gives me a input error so it doesnt even want to reach my Converter so i made the input parameter a VARCHAR(15) to take all kinds of inputs.
You can make some educated guesses on the date format, there's however limit on how much you can guess.
Canonical dates ussually are ISO compatible so yyyy-mm-dd - I've never seen something like 2017-31-01.
The problem is when you get something like 11-11-2011 or - even worse - 10/11/12. There's no way to figure that out if you have no additional information.
The best possible fix i found was the following(works for almost all formats)
https://i.stack.imgur.com/MLARE.png
This way it picks up which format whatever PC you are using is using and sends a standardized format to SQL
Related
Today I had to use a SQLite database for the first time and I really wondered about the display of a DATETIME column like 1411111200. Of course, internally it has to be stored as some integer value to be able to do math with it. But who wants to see that in a grid output, which is clearly for human eyes?
I even tried two programs, SQLiteStudio and SQLite Manager, and both don't even have an option to change this (at least I couldn't find it).
Of course with my knowledge about SQL it didn't take long to find out what the values mean - this query displays it like I expected:
select datetime(timestamp, 'unixepoch', 'localtime'), * from MyTable
But that's very uncomfortable when working with a GUI Tool. So why? Just because? Unix nerds? Or did I just get a wrong impression because I accidentally tried the only 2 Tools which are bad?
(I also appreciate comments on which tools to use or where I can find the hidden settings.)
Probably because sqlite doesn't have a first-class date type — how would a GUI tool know which columns are supposed to contain dates?
The question implies that a column of datatype DATETIME can only hold valid datetimes. But that's not true in SQLite: you can put any number or string value and it will be stored and displayed like it is.
To find out what the most "natural" way for a timestamp in SQLite would be, I created a table like this:
CREATE TABLE test ( timestamp DATETIME DEFAULT ( CURRENT_TIMESTAMP ) );
The result is a display in human readable format (2014-09-22 10:56:07)! But in fact it is saved as string, and I cannot imagine any serious software developer who would like that. Any comments?
That original database from the question, having datetimes as unixepoch, is not because of its table definition, but because the inserted data was like that. And that was probably the best possible option how to do it.
So, the answer is, those tools cannot display the datetime in human readable format, because they cannot know how it was encoded. It can be the number of seconds since 1970 or anything else, and it could even be different from row to row. What a mess.
From Wikipedia:
A common criticism is that SQLite's type system lacks the data
integrity mechanism provided by statically typed columns in other
products. [...] However, it can be implemented with constraints
like CHECK(typeof(x)='integer').
From the authors:
[...] most other SQL database engines are statically typed and so some
people feel that the use of manifest typing is a bug in SQLite. But
the authors of SQLite feel very strongly that this is a feature. The
use of manifest typing in SQLite is a deliberate design decision which
has proven in practice to make SQLite more reliable and easier to use,
especially when used in combination with dynamically typed programming
languages such as Tcl and Python.
I have a lot of different date format that one of my field can contain. And I'm trying to parse it but it some times doesn't understand the format at all and returns 1900-01-01.
Or sometimes, it invert months, days and year: 2023-12-11 instead of 2012-11-23.
The field is contained in a total of 1500-2500 excel files, that are produced by some kind of scanner. Dates and time are in different cases.
I've seen different formats such as these so far:
yyyy-mm-dd or mm/dd/yy and some others (that i cant find because i dont want to spend the day oppenning random excel files hoping to find a different format ^^')
So... I've tried parsing it at hand (Substring of the different fields), but it still has bugs, so:
Is there any date parsing tool for VB that works often?
I imagine there is a library or something that can parse dates from almost any format already coded, and if I could avoid to recode it I'd be quite happy :)
No, of course there is nothing that can parse dates in any (unknown) format. How should it know what to do with 9/10/11? That can be anything.
So you can use TryParse or TryParseExact (you can even pass a string[] for multiple allowed formats) and pass the correct CultureInfo.
Here is my problem. the date that i got from my database contains "12/31/2013". Based on this date, the format is mm/dd/yy. Now the question is how do i makes it that no matter what format of the date in the user's computer, they will always read the date "12/31/2013" as mm/dd/yy instead of example dd/mm/yy which when it reads it contains an error due to there is no 31 month. i try the split method on the date i receive from my database but i coudn't get it to confirm to the format that is independent from the user's computer
Is your date being stored in your database as an actual date format, or as a string?
Remember that DateTime.Parse by default, uses the current user's current system date/time formatting settings (so UK users are dd/MM/yyyy, but US users are MM/dd/yyyy). If you want uniform parsing then use DateTime.ParseExact and specify an exact parsing format string.
One rule of thumb that's useful to remember is that "if you're ever using String.Split, you're probably doing something wrong" (I'll make exceptions for quick-and-dirty by-design programs, but for parsing a Format-string, Regular-expression, or Finite state machine is more performant (less string allocations) and less brittle.
Back on-topic, if your database is storing objects as a date or datetime then don't use strings at all. Use the .GetDateString(int) method of IDataReader or typed field properties of EF classes.
How did you get a date from your database? Did you store the date as a string? If at all possible, consider keeping the date as a DateTime variable rather than a string. If not possible, look into the DateTime.TryParse method which supports internationalization and should be able to understand with the user's UI localization settings.
Its not clear if you want to read the same format from the database or display it on the screen (UI)
If its from the sql server, consider using convert <- follow this link
I have jusrt uploaded an Access Database to SQL Server 2008 and the numeric fields have been changed to things like:
2.5364E-05,
2.5364E-05,
2.7598E-05,
2.8425E-05,
2.7598E-05,
2.5364E-05,
2.5364E-05,
I have seen this happen before, but now i need to know how to resolve it.
Is there any way to convert the numbers back, or avoid the problem in the first place?
Thanks all!
C
It's very unlikely that your data has actually been changed. This is a presentational effect that happens with the decimal data type.
Have you tried formatting the data using CONVERT(VarChar, ...)? What is the format you're expecting?
Is there a way to change the default format of a date in Postgres?
Normally when I query a Postgres database, dates come out as yyyy-mm-dd hh:mm:ss+tz, like 2011-02-21 11:30:00-05.
But one particular program the dates come out yyyy-mm-dd hh:mm:ss.s, that is, there is no time zone and it shows tenths of a second.
Apparently something is changing the default date format, but I don't know what or where. I don't think it's a server-side configuration parameter, because I can access the same database with a different program and I get the format with the timezone.
I care because it appears to be ignoring my "set timezone" calls in addition to changing the format. All times come out EST.
Additional info:
If I write "select somedate from sometable" I get the "no timezone" format. But if I write "select to_char(somedate::timestamptz, 'yyyy-mm-dd hh24:mi:ss-tz')" then timezones work as I would expect.
This really sounds to me like something is setting all timestamps to implicitly be "to_char(date::timestamp, 'yyyy-mm-dd hh24:mi:ss.m')". But I can't find anything in the documentation about how I would do this if I wanted to, nor can I find anything in the code that appears to do this. Though as I don't know what to look for, that doesn't prove much.
Never mind :'(
I found my problem. I was thinking that I was looking directly at the string coming back from the database. But I was overlooking that it was reading it as a Timestamp and then converting the Timestamp to a string. This was buried inside a function called "getString", which is what threw me off. I was thinking it was ResultSet.getString, but it was really our own function with the same name. Oops. What idiot wrote that function?! Oh, it was me ...
Thanks to all who tried to help. I'll give you each an upvote for your trouble.
I believe the table columns are specified differently. Try these variants:
timestamp
timestamp(0) no millis
timestamptz with timezone
timestamptz(0) with timezone, no millis
With which client are you running the select statements? Formatting the output is the application's responsibility, so without knowing which application you use to display the data, it's hard to tell.
Assuming you are using psql, you can change the date format using the SET command:
http://www.postgresql.org/docs/current/static/sql-set.html
Which is essentially a way to change the configuration parameters. The ones that are responsible for formatting data are documented here:
http://www.postgresql.org/docs/current/static/runtime-config-client.html#RUNTIME-CONFIG-CLIENT-FORMAT
Daniel tells me to post my findings as an answer and accept it to close the question. Okay.
I found that the date format I was seeing that did not include a time zone was not what was coming directly from Postgres, but that there were a couple of function calls that I was missing that converted the incoming date to a java.util.Timestamp, and then from the java.util.Timestamp to a String. It was in this conversion from the Timestamp to the String that the time zone was defaulting to EST.
In my own humble defense, my mistake was not as dumb as it may sound. :-0 We had the execution of the query in a subclass that read the results into a List, which we do to allow modification of the query results before output. (In this case we are adding a coule of columns that are derived from the stored columns.) Then we have a set of functions that resemble the JDBC functions to pull the data out of the List, so a calling program can easily switch from processing a query directly to processing the List. When I was wrestling with the date format problem, it just didn't register on me that I wasn't looking at "real JDBC", but at "simulated JDBC" calls.