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https://github.com/andizzle/rwdb

Database wrapper that manage read write connections
https://github.com/andizzle/rwdb

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Database wrapper that manage read write connections

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# rwdb



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Database wrapper that manage read write connections



## Install



```

go get github.com/andizzle/rwdb

```



## Create connections



```go

package main



import "github.com/andizzle/rwdb"



var conns = []string{

        "tcp://user:pass@write/dbname",

        "tcp://user:pass@read1/dbname",

        "tcp://user:pass@read2/dbname",

        "tcp://user:pass@read3/dbname",

}



// unable to open write will cause an error

db, err := rwdb.Open("driver", conns...)

```



## Rotation read and Sticky read



Query a database rotate the use of database connections



### Basic usage



```go

db, err := rwdb.Open("driver", conns...)



// Use the first connection

db.QueryContext(ctx)



// Use the next connection

db.QueryContext(ctx)

```



Execute a statement will cause all subsequent queries to use the write connection (sticky connection). This is to allow the 

immediate reading of records that have been written to the database during the current request cycle. 



```go

db, err := rwdb.Open("driver", conns...)



// Use the next connection

db.QueryContext(ctx)



// Use the write conenction

db.ExecContext(ctx)



// Use the write connection

db.Query()

```



Sticky can be turned off

```go

db.SetSticky(false)

```



### A more practical example



The db is marked as modified if there's a successful `Write` to the databse, which turns on the sticky logic. 

However, the real world usecase would require `modified` value to be reset on each request session.



Here's what we can do:



```go

db, err := rwdb.Open("driver", conns...)



func RecordUserLogin() {

        d := db.New()       // This will make sure the following read are not affected by 

                            // other sessions' write action



        d.Query("SELECT * from `users` where id = ?")

        ...

        d.Exec("UPDATE `users` set last_login_at = now();")

        d.Query(...)        // Connection is set to the writer

}

```



## License



[License](https://github.com/andizzle/rwdb/blob/master/LICENSE)