Question

am using this connection string to connect to mysql from java:

jdbc:mysql://localhost:3306/db?noDatetimeStringSync=true&useUnicode=yes&characterEncoding=UTF-8

is it possible to set the session variable in the string so that SET UNIQUE_CHECKS=0; would be executed upon connecting to server? the obvious

jdbc:mysql://localhost:3306/db?noDatetimeStringSync=true&useUnicode=yes&characterEncoding=UTF-8&unique_checks=0

doesn t seem to work, based on the fact that

jdbc:mysql://localhost:3306/db?noDatetimeStringSync=true&useUnicode=yes&characterEncoding=UTF-8&unique_checks=blahblah`

doesn t generate any error.

Cheers!

Answer 1

How about using sessionVariables:

 jdbc:mysql://localhost:3306/db?noDatetimeStringSync=true&useUnicode=yes&characterEncoding=UTF-8&sessionVariables=unique_checks=0

Answer 2

Your question is thus more "How do I concat Strings in Java?" ?

If so, then just use the + operator:

int uniqueChecks = 0; // Assign session variable here.
String url = "jdbc:mysql://localhost:3306/db?unique_checks=" + uniqueChecks;

Alternatively you can also use String#format() wherein you can use the %d pattern to represent a decimal:

int uniqueChecks = 0; // Assign session variable here.
String url = String.format("jdbc:mysql://localhost:3306/db?unique_checks=%d", uniqueChecks);

Answer 3

You can use Statement.execute() to run pretty much every statement the DB understands, including such a SET-statement.

The advantage of using an URL parameter or a dedicated method is that the JDBC-driver is actually aware that the option was set and can react accordingly. This may or may not be useful or necessary for this particular option, but it s vital for other options (for example toggling autocommit with such a statement is a very bad idea).

Answer 4

BalusC, thanks for a reply! actually I need to do that in Talend etl tool(which itself is a java code generator) and the only line i can edit is the "jdbc:mysql://localhost:3306/db?noDatetimeStringSync=true&useUnicode=yes&characterEncoding=UTF-8" string, which gets translated to this java code:

String url_tMysqlBulkExec_1 = "jdbc:mysql://"
+ "localhost" +
":" 
+ "3306" 
+ "/" 
+ "db" 
+ "?" 
+ "noDatetimeStringSync=true&useUnicode=yes&characterEncoding=UTF-8&unique_checks=0";

that s the limitation, sorry for not pointing that out earlier.

Answer 5

According to mysql docs, there is no possibility to set the unique_checks setting, i guess i need to look for other solution than URL parameters (Joachim, thanks for reminding me that these things are called "URL parameters" - help a lot while googling :)

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