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TypedRequest Protocol Reference
TypedRequest
public protocol TypedRequest : RequestThe protocol for requests that know how to decode database rows.
Typed requests can fetch if their associated type RowDecoder is able to decode rows (Row, value, record)
struct Player: RowConvertible { ... }
let request: ... // Some TypedRequest that fetches Player
try request.fetchCursor(db) // Cursor of Player
try request.fetchAll(db) // [Player]
try request.fetchOne(db) // Player?
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adapted(_:)Extension methodReturns an adapted typed request.
Declaration
Swift
public func adapted(_ adapter: @escaping (Database) throws -> RowAdapter) -> AdaptedTypedRequest<Self>
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fetchCursor(_:)Extension methodA cursor over fetched records.
let request: ... // Some TypedRequest that fetches Player let players = try request.fetchCursor(db) // Cursor of Player while let player = try players.next() { // Player ... }If the database is modified during the cursor iteration, the remaining elements are undefined.
The cursor must be iterated in a protected dispath queue.
Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchCursor(_ db: Database) throws -> RecordCursor<RowDecoder>Parameters
dbA database connection.
Return Value
A cursor over fetched records.
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fetchAll(_:)Extension methodAn array of fetched records.
let request: ... // Some TypedRequest that fetches Player let players = try request.fetchAll(db) // [Player]Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchAll(_ db: Database) throws -> [RowDecoder]Parameters
dbA database connection.
Return Value
An array of records.
-
fetchOne(_:)Extension methodThe first fetched record.
let request: ... // Some TypedRequest that fetches Player let player = try request.fetchOne(db) // Player?Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchOne(_ db: Database) throws -> RowDecoder?Parameters
dbA database connection.
Return Value
An optional record.
-
fetchCursor(_:)Extension methodA cursor over fetched values.
let request: ... // Some TypedRequest that fetches String let strings = try request.fetchCursor(db) // Cursor of String while let string = try strings.next() { // String ... }If the database is modified during the cursor iteration, the remaining elements are undefined.
The cursor must be iterated in a protected dispath queue.
Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchCursor(_ db: Database) throws -> DatabaseValueCursor<RowDecoder>Parameters
dbA database connection.
Return Value
A cursor over fetched values.
-
fetchAll(_:)Extension methodAn array of fetched values.
let request: ... // Some TypedRequest that fetches String let strings = try request.fetchAll(db) // [String]Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchAll(_ db: Database) throws -> [RowDecoder]Parameters
dbA database connection.
Return Value
An array of values.
-
fetchOne(_:)Extension methodThe first fetched value.
The result is nil if the request returns no row, or if no value can be extracted from the first row.
let request: ... // Some TypedRequest that fetches String let string = try request.fetchOne(db) // String?Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchOne(_ db: Database) throws -> RowDecoder?Parameters
dbA database connection.
Return Value
An optional value.
-
fetchCursor(_:)Extension methodA cursor over fetched values.
let request: ... // Some TypedRequest that fetches String let strings = try request.fetchCursor(db) // Cursor of String while let string = try strings.next() { // String ... }If the database is modified during the cursor iteration, the remaining elements are undefined.
The cursor must be iterated in a protected dispath queue.
Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchCursor(_ db: Database) throws -> ColumnCursor<RowDecoder>Parameters
dbA database connection.
Return Value
A cursor over fetched values.
-
fetchAll(_:)Extension methodAn array of fetched values.
let request: ... // Some TypedRequest that fetches String let strings = try request.fetchAll(db) // [String]Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchAll(_ db: Database) throws -> [RowDecoder]Parameters
dbA database connection.
Return Value
An array of values.
-
fetchOne(_:)Extension methodThe first fetched value.
The result is nil if the request returns no row, or if no value can be extracted from the first row.
let request: ... // Some TypedRequest that fetches String let string = try request.fetchOne(db) // String?Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchOne(_ db: Database) throws -> RowDecoder?Parameters
dbA database connection.
Return Value
An optional value.
-
fetchCursor(_:)Extension methodA cursor over fetched optional values.
let request: ... // Some TypedRequest that fetches Optional<String> let strings = try request.fetchCursor(db) // Cursor of String? while let string = try strings.next() { // String? ... }If the database is modified during the cursor iteration, the remaining elements are undefined.
The cursor must be iterated in a protected dispath queue.
Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchCursor(_ db: Database) throws -> NullableDatabaseValueCursor<RowDecoder._Wrapped>Parameters
dbA database connection.
Return Value
A cursor over fetched values.
-
fetchAll(_:)Extension methodAn array of fetched optional values.
let request: ... // Some TypedRequest that fetches Optional<String> let strings = try request.fetchAll(db) // [String?]Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchAll(_ db: Database) throws -> [RowDecoder._Wrapped?]Parameters
dbA database connection.
Return Value
An array of values.
-
fetchCursor(_:)Extension methodA cursor over fetched optional values.
let request: ... // Some TypedRequest that fetches Optional<String> let strings = try request.fetchCursor(db) // Cursor of String? while let string = try strings.next() { // String? ... }If the database is modified during the cursor iteration, the remaining elements are undefined.
The cursor must be iterated in a protected dispath queue.
Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchCursor(_ db: Database) throws -> NullableColumnCursor<RowDecoder._Wrapped>Parameters
dbA database connection.
Return Value
A cursor over fetched values.
-
fetchAll(_:)Extension methodAn array of fetched optional values.
let request: ... // Some TypedRequest that fetches Optional<String> let strings = try request.fetchAll(db) // [String?]Throws
A DatabaseError is thrown whenever an SQLite error occurs.Declaration
Swift
public func fetchAll(_ db: Database) throws -> [RowDecoder._Wrapped?]Parameters
dbA database connection.
Return Value
An array of values.
-
fetchCursor(_:)Extension methodA cursor over fetched rows.
let request: ... // Some TypedRequest that fetches Row let rows = try request.fetchCursor(db) // RowCursor while let row = try rows.next() { // Row let id: Int64 = row[0] let name: String = row[1] }Fetched rows are reused during the cursor iteration: don’t turn a row cursor into an array with
Array(rows)orrows.filter { ... }since you would not get the distinct rows you expect. UseRow.fetchAll(...)instead.For the same reason, make sure you make a copy whenever you extract a row for later use:
row.copy().If the database is modified during the cursor iteration, the remaining elements are undefined.
The cursor must be iterated in a protected dispath queue.
Throws
A DatabaseError is thrown whenever an SQLite error occurs.Parameters
dbA database connection.
Return Value
A cursor over fetched rows.
-
fetchAll(_:)Extension methodAn array of fetched rows.
let request: ... // Some TypedRequest that fetches Row let rows = try request.fetchAll(db)Throws
A DatabaseError is thrown whenever an SQLite error occurs.Parameters
dbA database connection.
Return Value
An array of fetched rows.
-
fetchOne(_:)Extension methodThe first fetched row.
let request: ... // Some TypedRequest that fetches Row let row = try request.fetchOne(db)Throws
A DatabaseError is thrown whenever an SQLite error occurs.Parameters
dbA database connection.
Return Value
A,n optional rows.