I'm wondering if anyone has any clarification on the difference between the following statements using sqlite3 gem with ruby 1.9.x:
#db.execute("INSERT INTO table(a,b,c) VALUES (?,?,?)",
some_int, other_int, some_string)
and
#db.execute("INSERT INTO table(a,b,c) VALUES (#{some_int},"+
+"#{some_int}, #{some_string})")
My problem is: When I use the first method for insertion, I can't query for the "c" column using the following statement:
SELECT * FROM table WHERE c='some magic value'
I can use this:
"SELECT * FROM table WHERE c=?", "some magic value"
but what I really want to use is
"SELECT * FROM table WHERE c IN ('#{options.join("','")}')"
And this doesn't work with the type of inserts.
Does anyone know what the difference is at the database level that is preventing the IN from working properly?
I figured this out quite a while ago, but forgot to come back and point it out, in case someone finds this question at another time.
The difference turns out to be blobs. Apparently when you use the first form above (the substitution method using (?,?)) SQLite3 uses blogs to enter the data. However, if you construct an ordinary SQL statement, it's inserted as a regular string and the two aren't equivalent.
Insert is not possible to row query but row query used in get data that time this one working.
SQLite in you used in mobile app that time not work bat this row query you write in SQLite Browse in that work
Related
I want to read from a table, change a couple column values for a few lines in a query, then update those lines on the same table.
I'm using SAP BODS, and that's what I tried:
I was about to insert images but just found out I can't insert images until 10 rep.
Anyway, I created a DataFlow where I have the same table as source and target.
A query to filter (using where) and change values (using mapping). And then a Table Comparison (where I expected those lines to be set to update, in this particular case), set table name on first entry, then PK in 'input primary key' and then the two columns I want to change in 'Compare columns'. No other changes from default that I can recall.
Got no warnings on 'validate all', and on execution I receive an ORA-00001 for the PK.
So ... I thought the Table Comparison would try to update, but seems like it's trying to insert instead. I want to know what I'm doing wrong and how could I get the job to do those updates. Thanks in advance.
Ps. I did search SO before asking and didn't find anything relevant.
Ok
So, turns out I just found what's going on a few minutes after posting the question.
Wasn't sure if I should answer my own question and took a look at this Etiquette for answering your own question
and decided to come back here and answer my own question.
For some reason I got stuck thinking that it was something to do with the Table Comparison trying to insert a line with a PK that's already there, instead of doing the update I wanted.
But after going back to the job to take another look at the issue, it occurred to me that maybe the problem could be a duplicate in the incoming data set. Made a few adjustment to filter those, and voilà.
I have a Pesky SSRS report Problem where in the main query of my report has a condition that can have more than 1000 choices and when user selects all it will fail as my backend database is Oracle. I have done some research and found a solution that would work.
Solution is
re-writing the in clause something like this
(1,ColumnName) in ((1,Searchitem1),(1,SearchItem2))
this will work however when I do this
(1,ColumnName) in ((1,:assignedValue))
and pass just one value it works. But when I pass more than one value it fails and gives me ORA-01722: Invalid number error
I have tried multiple combination of the same in clause but nothing is working
any help is appreciated...
Wild guess: your :assignedValue is a comma-separated list of numbers, and Oracle tries to parse it as a single number.
Passing multiple values as a single value for an IN query is (almost) never a good idea - either you have to use string concatenation (prone to SQL injection and terrible performance), or you have to have a fixed number of arguments to IN (which generally is not what you want).
I'd suggest you
INSERT your search items into a temporary table
use a JOIN with this search table in your SELECT
I have a query that looks like this:
select * from foo where id in (:ids)
where the id column is a number.
When running this in TOAD version 11.0.0.116, I want to supply a list of ids so that the resulting query is:
select * from foo where id in (1,2,3)
The simple minded approach below gives an error that 1,2,3 is not a valid floating point value. Is there a type/value combination that will let me run the desired query?
CLARIFICATION: the query as shown is how it appears in my code, and I am pasting it into TOAD for testing the results of the query with various values. To date I have simply done a text replacement of the bind variable in TOAD with the comma separated list, and this works fine but is a bit annoying for trying different lists of values. Additionally, I have several queries of this form that I test in this way, so I was looking for a less pedestrian way to enter a list of values in TOAD without modifying the query. If this is not possible, I will continue with the pedestrian approach.
As indicated by OldProgrammer, the Gerrat's answer that "You can't use comma-separated values in one bind variable" in the indicated thread correctly answers this question as well.
We have a database with some fields that are varchar(max) which could contain lots of text however I have a situation where I only want to select the first for example 300 characters from the field for a paginated table of results on a MVC web site for a "preview" of the field.
for a simplified example query where I want to get all locations to display in the table
(this would be paginated, so I don't just get everything - I get maybe 10 results at a time):
return db.locations;
However this gives me a location object with all the fields containing the massive amounts of text which is very time consuming to execute.
So what I resorted to before was using SQL stored procedures with the:
LEFT(field, 300)
to resolve this issue and then in the Linq to SQL .dbml file included the stored procedure to return a "location" object for the result.
However I have many queries and I don't want to have to do this for every query.
This maybe a simple solution, but I am not sure how I can phrase this on a search engine, I would appreciate anyone who can help me with this problem.
You can use functions that directly translate to those functions too, this is useful when you need to translate code that functionally works just fine in SQL at no risk in LINQ.
Have a look at System.Data.Objects.EntityFunctions
Locations.Select(loc=>System.Data.Objects.EntityFunctions.Left(loc.Field,300))
This will get directly translated into a LEFT on the server side.
EDIT: I misread LEFT for LTRIM. Here's all the String functions that can't be used in LINQ to SQL. Have you tried String.Substring()?
Your best option is to map the stored procedure and continue using it. Here is an excellent article with screen shots showing you how to do so.
If you're not using the designer tool you can also call ExecuteCommand against the DataContext. It isn't pretty, but it's what we have for now.
I found something like this worked for me:
return from locationPart in db.locations
select new LocationPart
{
Description = locationPart.description,
Text = locationPart.text.Substring(0,300)
};
Not ideal because I have to use "select new" to return a a different object, but it seems to work.
I am writing a simple program to insert rows into a table.But when i started writing the program i got a doubt. In my program i will get duplicate input some times. That time i have to notify the user that this already exists.
Which of the Following Approaches is good to Use to achieve this
Directly Perform Insert statement will get the primary key violation error if it is duplicate notify otherwise it will be inserted. One Query to Perform
First make a search for the primary key values. If found a Value Prompt User. Otherwise perform insert operation.For a non-duplicate row this approach takes 2 queries.
Please let me know trade-offs between these approaches. Which one is best to follow ?
Regards,
Sunny.
I would choose the 2nd approach.
The first one would cause an exception to be thrown which is known to be very expensive...
The 2nd approach would use a SELECT count(*) FROM mytable WHERE key = userinput which will be very fast and the INSERT statement for which you can use the same DB connection object (assuming OO ;) ).
Using prepared statements will pre-optimize the queries and I think that will make the 2nd approach much better and mre flexible than the first one.
EDIT: depending on your DBMS you can also use a if not exists clause
EDIT2: I think Java would throw a SQLExcpetion no matter what went wrong, i.e. using the 1st approach you wouldn't be able to differ between a duplicate entry or an unavailable database without having to parse the error message - which is again a point for using SELECT+INSERT (or if not exists)