How to create prepared statements?

[Sisso]

I am confused about how I can create a prepared statement. The lack of information in documentation a bit of dig into the code looks it is not possible.

Something like:

func initalization(c *gocql.Session) {

   getUserStm = c.Prepare("select * from user wher id = ?")

}

func  GetUser(c *gocql.Session, id string) .. {

   return c.Exec(getUserStm.bind("id"))...

}

How can I create all the prepared statements during app initialization, then just bind variables when I need to call it? It is possible?

I am aware there are some adhoc "cache", but this doesn't tackle the issue of invalid queries are only detected during execution after the approval of the release. For now, the only solution I find is to smoke test all my queries before switch traffic. That is very code intensive and not always possible.

[Martin Sucha]

Hello,

On Thu, Jan 28, 2021 at 11:34 AM Sisso <sis...@gmail.com> wrote:

I am confused about how I can create a prepared statement. The lack of information in documentation a bit of dig into the code looks it is not possible.

We have a pull request for adding package documentation, it will be merged soon: https://github.com/gocql/gocql/pull/1513

 

Something like:

func initalization(c *gocql.Session) {

   getUserStm = c.Prepare("select * from user wher id = ?")

}

func  GetUser(c *gocql.Session, id string) .. {

   return c.Exec(getUserStm.bind("id"))...

}

How can I create all the prepared statements during app initialization, then just bind variables when I need to call it? It is possible?

There is no exported API for prepared statements. gocql manages it's own internal cache of prepared statements, all data manipulation queries (select/update/insert/delete/batch) are automatically prepared.

> I am aware there are some adhoc "cache", but this doesn't tackle the issue of invalid queries are only detected during execution after the approval of the release. For now, the only solution I find is to smoke test all my queries before switch traffic. That is very code intensive and not always possible.

So your use case would be to verify that the syntax of the statements is correct in advance? At the moment the only way to find out is to actually execute the query (for example in tests, as you mentioned). Note that preparing the statement would not catch all reasons why a query might fail anyway (e.g. if you don't bind the value), so I think having tests in your code is a better option.

Martin

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