I have a sqlite3 prepared statement. I know the number of values to bind to this prepared statement, but don't know their data types. (I just get a CSV file with the right values). Is there a generic bind method I can use for this? All the bind method in the documentation are for a specific data type.
I know that sqlite3 uses a dynamic type system. But it doesn't help if you are using the C API due to the absence of a generic bind method.
Any ideas/tricks anyone has tried?
The C API does not have a generic bind method because the C language does not have a generic type. Simply use the bind method for the type that you have, if it is wrong then sqlite will convert it for you.
Related
Does PeopleCode have something similar to reflection in C# whereby I can access a variable with the variable name stored in a string? I am aware of the # operator but I think it only applies to fields and records (correct me if I am wrong. I tried and couldn't get it to work.)
Basically, I need to access a Component variable by name with the name itself being variable.
You can do it by # :
Local string &sValue1 = "var1";
getting the value :
winmessage(#(&sValue1));
I already used the search here (and other forums as well) but haven't found an answer exacty to what I'm trying to do.
I know that it can easily be done in some other way, and this is just a small sandbox-framework I'm coding for a University course... in a real environment I'd just take Spring, Hibernate etc.
So what I did was coding myself a small generic Data Access Layer with POJOs, working with generic methods to retrieve, check or insert data to the database (Oracle). Most of this is done through PreparedStatements.
This is working as long as I don't have joins... is it possible to put in a Column as parameter?
Example:
Table A has Attribute X + others
Table B has Attribute Y + others
PreparedStatement with query SELECT * FROM A,B WHERE "A"."X" = ?
And then fill in "B"."Y" as the parameter...
The database doesn't throw me an error or exception, but the ResultSet returned after executing the statement is empty. Is it just not possible to do, or am I just missing some escaping?
I'm using PreparedStatement.setString(int index, String value) to fill in the parameter... in lack of ideas which other setX method I could use...
Again, in a real project I'd never code that myself, but rather use something like Spring or Hibernate and not re-invent the wheel, but I see it as an interesting exercise to code such a generic small data access layer myself.
No, JDBC does not allow this. Only column values can be set. If you want to make dynamic changes to the sql statement you will have to do it before you create the PreparedStatement.
I found a query like select cast (:v as customtabletype) from dual.
Not able to understand what is the meaning of above line, written as dynamic query.
:<variablename>, in your case ":v", is what is known as a bind variable.
Essentially, this is a placeholder which is replaced with another value as the SQL statement is executed.
For more in-depth reading it is probably worth looking for bind variables in the Oracle documentation, as there is a lot of information available on why they're used and their benefits.
I would like to know how to accomplish this task. I've looked at CASE, DECODE or IF condition and I'm not able to make it work. My goal is to pass a block of predefined column/value pair constructed from ASP.NET data to my Oracle stored procedure. I am trying to only update certain columns out of many to preserve other columns not needing updates. So here's my set up:
Stored procedure:
UpdateSelectedColumns(myValuePairString, updatedBy)
-- Passed variable from ASP.NET, myValuePairString = 'col1 = 10,col2 = 'Dog''
-- update statement final
UPDATE MyTable
SET
col1 = 10,
col2 = 'Dog'
col3 = 'john';
COMMIT;
Thank you in advance...
Ricky
For once I'm gonna advise to not use a stored proc. There is no point here in using a stored procedure.
As it is your stored procedure would blindly accept its arguments and execute the update without adding any value. Furthermore, by using this procedure, you preclude the use of binds and exposes yourself to bugs (whenever you encouner a value with a quote '), performance hit and SQL injection vulnerability.
The advantage of PL/SQL (simple transparent binding, transparent use and reuse of cursors, strict static SQL parsing and metadata dependancy) are all pointless if you take an aribtrary string as argument and put it in a dynamic cursor.
You'll be better off to use your language native cursors and use bind variables.
If you really want to use PL/SQL, replace your single argument with a couple of tables. One for the column names, one for the variable values. You could then use DBMS_SQL to parse the statement and use appropriate bind variables. You'll need some convention to be able to parse date, number and character values. You'll need to read metadata from the database to check the datatypes. This would be a lot of code for not a bit of value.
So I'm transferring an old filemaker database to MySQL and some repeating fields are causing me some problems. I've read that the ODBC standard support those fields, only when their types is "Text" and that each repetition is concatenated with a certain delimiter (see page 47 (PDF)). However, I just can't reproduce this. All I get is the first repetition.
If I export the database to the .csv format, the fields are correctly concatenated, so I'm not completely stuck, but if possible, I'd like to be able to obtain the same result with the ODBC connection. Thanks!
With JDBC and Filemaker 12 I can access the repeating field using brackets as it was table beginning with index 1.
It should be the same in ODBC.
Of course I recommend to normalize but it can help to know there is other options.
In my experience the documentation about repeating fields is a lie. :)
If you can get it to work, please, please post an answer. But I imagine you'll have to do the workaround using the csv export.
My recommendation regarding this would be to normalize the repeating fields to a separate table within FileMaker and then perform the transfer of the data. You can create a related table in FileMaker and then use a script to populate the table with the repeating field values. Let me know if you need assistance writing such a script.
I want to provide details about #Signix answer above. I was able to fetch repeating fields from JDBC but it's tricky. At page 30 of FileMaker "ODBC and JDBC Guide", it states:
Note FileMaker repeating fields are supported like arrays.
Example
INSERT INTO mytable(repField[3]) VALUES (‘this is rep 3’)
SELECT repField[1], repField[2] FROM mytable
This is the only documentation! So in theory you could use this query:
ResultSet resultSet = fmStatement.executeQuery("SELECT id, repField[1], repField[2] FROM mytable");
But the tricky part is getting the results. The only way seems to use the column index.
System.out.println(resultSet.getString("repField[1]")); // fails, throws FMSQLException
System.out.println(resultSet.getString("repField[2]")); // fails, throws FMSQLException
System.out.println(resultSet.getString("repField")); // returns repField[1]
System.out.println(resultSet.getString(2)); // returns repField[1]
System.out.println(resultSet.getString(3)); // returns repField[2]
I think the reason is because fields are being named without their bracket parts.
System.out.println(resultSet.getMetaData().getColumnName(1)); // returns "id"
System.out.println(resultSet.getMetaData().getColumnName(2)); // returns "repField"
System.out.println(resultSet.getMetaData().getColumnName(3)); // returns "repField"
So when using resultSet.getString("repField") it returns the first column value with that name. It's stupid but it works.