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diff --git a/vendor/github.com/hashicorp/go-memdb/README.md b/vendor/github.com/hashicorp/go-memdb/README.md new file mode 100644 index 0000000..080b744 --- /dev/null +++ b/vendor/github.com/hashicorp/go-memdb/README.md @@ -0,0 +1,146 @@ +# go-memdb [](https://circleci.com/gh/hashicorp/go-memdb/tree/master) + +Provides the `memdb` package that implements a simple in-memory database +built on immutable radix trees. The database provides Atomicity, Consistency +and Isolation from ACID. Being that it is in-memory, it does not provide durability. +The database is instantiated with a schema that specifies the tables and indices +that exist and allows transactions to be executed. + +The database provides the following: + +* Multi-Version Concurrency Control (MVCC) - By leveraging immutable radix trees + the database is able to support any number of concurrent readers without locking, + and allows a writer to make progress. + +* Transaction Support - The database allows for rich transactions, in which multiple + objects are inserted, updated or deleted. The transactions can span multiple tables, + and are applied atomically. The database provides atomicity and isolation in ACID + terminology, such that until commit the updates are not visible. + +* Rich Indexing - Tables can support any number of indexes, which can be simple like + a single field index, or more advanced compound field indexes. Certain types like + UUID can be efficiently compressed from strings into byte indexes for reduced + storage requirements. + +* Watches - Callers can populate a watch set as part of a query, which can be used to + detect when a modification has been made to the database which affects the query + results. This lets callers easily watch for changes in the database in a very general + way. + +For the underlying immutable radix trees, see [go-immutable-radix](https://github.com/hashicorp/go-immutable-radix). + +Documentation +============= + +The full documentation is available on [Godoc](https://pkg.go.dev/github.com/hashicorp/go-memdb). + +Example +======= + +Below is a [simple example](https://play.golang.org/p/gCGE9FA4og1) of usage + +```go +// Create a sample struct +type Person struct { + Email string + Name string + Age int +} + +// Create the DB schema +schema := &memdb.DBSchema{ + Tables: map[string]*memdb.TableSchema{ + "person": &memdb.TableSchema{ + Name: "person", + Indexes: map[string]*memdb.IndexSchema{ + "id": &memdb.IndexSchema{ + Name: "id", + Unique: true, + Indexer: &memdb.StringFieldIndex{Field: "Email"}, + }, + "age": &memdb.IndexSchema{ + Name: "age", + Unique: false, + Indexer: &memdb.IntFieldIndex{Field: "Age"}, + }, + }, + }, + }, +} + +// Create a new data base +db, err := memdb.NewMemDB(schema) +if err != nil { + panic(err) +} + +// Create a write transaction +txn := db.Txn(true) + +// Insert some people +people := []*Person{ + &Person{"joe@aol.com", "Joe", 30}, + &Person{"lucy@aol.com", "Lucy", 35}, + &Person{"tariq@aol.com", "Tariq", 21}, + &Person{"dorothy@aol.com", "Dorothy", 53}, +} +for _, p := range people { + if err := txn.Insert("person", p); err != nil { + panic(err) + } +} + +// Commit the transaction +txn.Commit() + +// Create read-only transaction +txn = db.Txn(false) +defer txn.Abort() + +// Lookup by email +raw, err := txn.First("person", "id", "joe@aol.com") +if err != nil { + panic(err) +} + +// Say hi! +fmt.Printf("Hello %s!\n", raw.(*Person).Name) + +// List all the people +it, err := txn.Get("person", "id") +if err != nil { + panic(err) +} + +fmt.Println("All the people:") +for obj := it.Next(); obj != nil; obj = it.Next() { + p := obj.(*Person) + fmt.Printf(" %s\n", p.Name) +} + +// Range scan over people with ages between 25 and 35 inclusive +it, err = txn.LowerBound("person", "age", 25) +if err != nil { + panic(err) +} + +fmt.Println("People aged 25 - 35:") +for obj := it.Next(); obj != nil; obj = it.Next() { + p := obj.(*Person) + if p.Age > 35 { + break + } + fmt.Printf(" %s is aged %d\n", p.Name, p.Age) +} +// Output: +// Hello Joe! +// All the people: +// Dorothy +// Joe +// Lucy +// Tariq +// People aged 25 - 35: +// Joe is aged 30 +// Lucy is aged 35 +``` + |