Active.Net.AddOnlyDb

F# package for lightweight, easily synchronizable data store based on SQLite.

Usage

Quick and detailed usage examples.

Active.Net.Net has helper functions for common stuff (Guid, Hash, Text to/from bytes, etc.)

Quick

open Active.Net.Database
// hash algorithm to calculate fact ids; use Active.Net.Hash for functional interface
let sha256() = new System.Security.Cryptography.SHA256Managed() :> HashAlgorithm

// create
let db = DbCore.access (DbCore.File "addonly.sqlite3") // or DbCore.InMemory
let aodb = AddOnlyDb.make db sha256 "kv" "hashes" "kvCurrent"
AddOnlyDb.createTablesAndIndices aodb |> ignore

// read
let printers =
	AddOnlyDb.API.db {
		let! values = AddOnlyDb.API.get guid (Property "printer")
		return values
	}

// write
let setPrinter printer =
	AddOnlyDb.API.db {
		return! AddOnlyDb.API.putWithObsoletes guid (Property "printer") printer printers
	}

// close
AddOnlyDb.close aodb

Detailed

open Active.Net.Database

/// open existing (but 'open' is a keyword); fails if missing
// DBLocation allows File or in-memory DB
let access (dbLocation:DbCore.DBLocation) =
    let db = DbCore.access dbLocation
    // turn on foreign-key check (optional)
    DbCore.executeNonQuery db {qury="PRAGMA foreign_keys=on";parameters=[]} |> ignore
	// hash algorithm to calculate fact ids; use Active.Net.Hash for functional interface
	let sha256() = new System.Security.Cryptography.SHA256Managed() :> HashAlgorithm
	// kv, hashes, kvCurrent: names of AddOnlyDb tables
    AddOnlyDb.make db Hash.sha256 "kv" "hashes" "kvCurrent"

/// create new
let create (dbLocation:DbCore.DBLocation) =
	DbCore.create dbLocation
	let aodb = access dbLocation
	AddOnlyDb.createTablesAndIndices aodb |> ignore
	aodb

/// close
let close aodb =
    AddOnlyDb.close aodb

// some GUID; use Active.Net.Guid for functional interface
let guid = System.Guid.ParseExact("66344F65-B009-4617-ADC7-93404DBABFC3", "D")

/// overwrite value, obsoleting existing
let private overwrite guid prop value =
    API.db {
        let! obsoletes = API.getHashKey (makeSearchKey (Some guid) (Some prop) None)
        do! API.putWithObsoletes guid prop value obsoletes
        return ()
    }

/// get single-valued property;
/// if there was a conflicting sync, this will return several values;
/// if there is no value, will return empty array
let getProp guid prop (unmarshal:byte[] -> 'a) : 'a[] Op= db {
    let! values = API.get guid prop
    return Array.map unmarshal values
}

// from Active.Net.Net
let private utf8Encoding = new System.Text.UTF8Encoding(false, true) // no BOM, throw on invalid bytes

let private utf8Bytes (s:string) = utf8Encoding.GetBytes(s)
let private utf8String (utf8bytes:byte[]) = utf8Encoding.GetString utf8bytes

let private displayNameToBytes = utf8Bytes
let private displayNameFromBytes = utf8String

let private stationDisplayNameProp = AddOnlyDb.Property "displayname"

let stationDisplayName stationId : string[] Op =
    getProp stationId stationDisplayNameProp displayNameFromBytes

let stationDisplayNameSet displayName stationId : unit Op =
    updateProp stationId stationDisplayNameProp (displayNameToBytes displayName)