intro

This project aims to simplify working with PostgreSQL in Swift by modelling/integrating relational concepts rather than imposing an object oriented world view on the database. The core concepts have previously been prototyped and verified in several languages, including Common Lisp and Go.

schemas

Schemas keep track of standalone definitions such as tables, indexes, sequences and enum types.

let scm = Schema()
let tbl = Table(scm, "tbl")

let cx = Cx(database: "swisql", user: "swisql", password: "swisql")
var tx = try! await cx.startTx()
try! await scm.create(inTx: tx)
try! await tx.commit()

tables

Tables keep track of their columns, keys and indexes.

let scm = Schema()
let tbl = Table(scm, "tbl1")
let col = IntColumn("col", tbl, primaryKey: true)

let cx = Cx(database: "swisql", user: "swisql", password: "swisql")
var tx = try! await cx.startTx()
try! await tbl.create(inTx: tx)
try! await tx.commit()

foreign keys

Foreign keys create the required columns in their tables automatically by default.

let scm = Schema()

let tbl1 = Table(scm, "tbl1")
let col = IntColumn("col", tbl1, primaryKey: true)

let tbl2 = Table(scm, "tbl2")
_ = ForeignKey("fkey", tbl2, [col], primaryKey: true)

records

Records are ordered sets of Column/Any tuples. Subscripting using typed columns accepts and returns the correct type.

let scm = Schema()
let tbl = Table(scm, "tbl")
let col = StringColumn("col", tbl, primaryKey: true)

let rec = Record()
rec[col] = "foo"
assert(rec[col]! == "foo")

The status of each field is tracked in the current context/transaction.

tx = try! await cx.startTx()
assert(!rec.stored([col], inTx: tx))
assert(rec.modified([col], inTx: tx))

try! await tbl.insert(rec, inTx: tx)
assert(rec.stored([col], inTx: tx))
assert(!rec.modified([col], inTx: tx))

rec[col] = "bar"
assert(rec.modified([col], inTx: tx))

try! await tbl.update(rec, inTx: tx)
assert(!rec.modified([col], inTx: tx))

enums

PostgreSQL enums require String raw values and implementing the Enum protocol.

enum TestEnum: String, Enum {
    case foo = "foo"
    case bar = "bar"
    case baz = "baz"
}

let scm = Schema()
let tbl = Table(scm, "tbl")
let col = EnumColumn<TestEnum>("col", tbl, primaryKey: true)

The enum type is created automatically with the column if it doesn't already exist, but needs to be committed before it can be used.

let cx = Cx(database: "swisql", user: "swisql", password: "swisql")
var tx = try! await cx.startTx()
try! await scm.create(inTx: tx)
try! await tx.commit()

let rec = Record()
rec[enumCol] = .foo
tx = try! await cx.startTx()
try! await tbl.insert(rec, inTx: tx)