LibraDB is a simple, persistent key/value store written in pure Go. The project aims to provide a working yet simple example of a working database. If you're interested in databases, I encourage you to start here.
This database accompanies my blog post on how to write a database from scratch.
To start using LibraDB, install Go and run go get
:
go get -u github.com/amit-davidson/LibraDB
package main
import "github.com/amit-davidson/LibraDB"
func main() {
path := "libra.db"
db, _ := LibraDB.Open(path, LibraDB.DefaultOptions)
tx := db.WriteTx()
name := []byte("test")
collection, _ := tx.CreateCollection(name)
key, value := []byte("key1"), []byte("value1")
_ = collection.Put(key, value)
_ = tx.Commit()
}
Read-only and read-write transactions are supported. LibraDB allows multiple read transactions or one read-write transaction at the same time. Transactions are goroutine-safe.
LibraDB has an isolation level: Serializable. In simpler words, transactions are executed one after another and not at the same time.This is the highest isolation level.
tx := db.WriteTx()
...
if err := tx.Commit(); err != nil {
return err
}
tx := db.ReadTx()
...
if err := tx.Commit(); err != nil {
return err
}
Collections are a grouping of key-value pairs. Collections are used to organize and quickly access data as each collection is B-Tree by itself. All keys in a collection must be unique.
tx := db.WriteTx()
collection, err := tx.CreateCollection([]byte("test"))
if err != nil {
return err
}
_ = tx.Commit()
The Collection.ID()
function returns an integer to be used as a unique identifier for key/value pairs.
tx := db.WriteTx()
collection, err := tx.GetCollection([]byte("test"))
if err != nil {
return err
}
id := collection.ID()
_ = tx.Commit()
Key/value pairs reside inside collections. CRUD operations are possible using the methods Collection.Put
Collection.Find
Collection.Remove
as shown below.
tx := db.WriteTx()
collection, err := tx.GetCollection([]byte("test"))
if err != nil {
return err
}
key, value := []byte("key1"), []byte("value1")
if err := collection.Put(key, value); err != nil {
return err
}
if item, err := collection.Find(key); err != nil {
return err
}
if err := collection.Remove(key); err != nil {
return err
}
_ = tx.Commit()