DatabaseFunction

The name of the SQL function

Creates an SQL function.

For example:

let fn = DatabaseFunction("succ", argumentCount: 1) { dbValues in
    guard let int = Int.fromDatabaseValue(dbValues[0]) else {
        return nil
    }
    return int + 1
}
db.add(function: fn)
try Int.fetchOne(db, sql: "SELECT succ(1)")! // 2

Creates an SQL aggregate function.

For example:

struct MySum: DatabaseAggregate {
    var sum: Int = 0

    mutating func step(_ dbValues: [DatabaseValue]) {
        if let int = Int.fromDatabaseValue(dbValues[0]) {
            sum += int
        }
    }

    func finalize() -> (any DatabaseValueConvertible)? {
        return sum
    }
}

let dbQueue = try DatabaseQueue()
let fn = DatabaseFunction("mysum", argumentCount: 1, aggregate: MySum.self)
try dbQueue.write { db in
    db.add(function: fn)
    try db.execute(sql: "CREATE TABLE test(i)")
    try db.execute(sql: "INSERT INTO test(i) VALUES (1)")
    try db.execute(sql: "INSERT INTO test(i) VALUES (2)")
    try Int.fetchOne(db, sql: "SELECT mysum(i) FROM test")! // 3
}

Returns an SQL expression that applies the function.

See https://github.com/groue/GRDB.swift/#sql-functions

An SQL function that returns the Swift built-in capitalized String property.

The function returns NULL for non-strings values.

This function is automatically added by GRDB to your database connections. It is the function used by the query interface’s capitalized:

let nameColumn = Column("name")
let request = Player.select(nameColumn.capitalized)
let names = try String.fetchAll(dbQueue, request)   // [String]

An SQL function that returns the Swift built-in lowercased String property.

The function returns NULL for non-strings values.

This function is automatically added by GRDB to your database connections. It is the function used by the query interface’s lowercased:

let nameColumn = Column("name")
let request = Player.select(nameColumn.lowercased())
let names = try String.fetchAll(dbQueue, request)   // [String]

An SQL function that returns the Swift built-in uppercased String property.

The function returns NULL for non-strings values.

This function is automatically added by GRDB to your database connections. It is the function used by the query interface’s uppercased:

let nameColumn = Column("name")
let request = Player.select(nameColumn.uppercased())
let names = try String.fetchAll(dbQueue, request)   // [String]

An SQL function that returns the Swift built-in localizedCapitalized String property.

The function returns NULL for non-strings values.

This function is automatically added by GRDB to your database connections. It is the function used by the query interface’s localizedCapitalized:

let nameColumn = Column("name")
let request = Player.select(nameColumn.localizedCapitalized)
let names = try String.fetchAll(dbQueue, request)   // [String]

An SQL function that returns the Swift built-in localizedLowercased String property.

The function returns NULL for non-strings values.

This function is automatically added by GRDB to your database connections. It is the function used by the query interface’s localizedLowercased:

let nameColumn = Column("name")
let request = Player.select(nameColumn.localizedLowercased)
let names = try String.fetchAll(dbQueue, request)   // [String]

An SQL function that returns the Swift built-in localizedUppercased String property.

The function returns NULL for non-strings values.

This function is automatically added by GRDB to your database connections. It is the function used by the query interface’s localizedUppercased:

let nameColumn = Column("name")
let request = Player.select(nameColumn.localizedUppercased)
let names = try String.fetchAll(dbQueue, request)   // [String]