zeus
483 lines
18 KiB
Swift
483 lines
18 KiB
Swift
/// A [common table expression](https://sqlite.org/lang_with.html) that can be
|
|
/// used with the GRDB query interface.
|
|
public struct CommonTableExpression<RowDecoder> {
|
|
/// The table name of the common table expression.
|
|
///
|
|
/// For example:
|
|
///
|
|
/// // WITH answer AS (SELECT 42) ...
|
|
/// let answer = CommonTableExpression(
|
|
/// named: "answer",
|
|
/// sql: "SELECT 42")
|
|
/// answer.tableName // "answer"
|
|
public var tableName: String {
|
|
cte.tableName
|
|
}
|
|
|
|
var cte: SQLCTE
|
|
|
|
/// Creates a common table expression from a request.
|
|
///
|
|
/// For example:
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player) ...
|
|
/// let p = CommonTableExpression(
|
|
/// named: "p",
|
|
/// request: Player.all(),
|
|
/// type: Void.self)
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player) ...
|
|
/// let p = CommonTableExpression(
|
|
/// named: "p",
|
|
/// request: SQLRequest<Player>(sql: "SELECT * FROM player"),
|
|
/// type: Void.self)
|
|
///
|
|
/// - parameter recursive: Whether this common table expression needs a
|
|
/// `WITH RECURSIVE` sql clause.
|
|
/// - parameter tableName: The table name of the common table expression.
|
|
/// - parameter columns: The columns of the common table expression. If nil,
|
|
/// the columns are the columns of the request.
|
|
/// - parameter request: A request.
|
|
private init(
|
|
recursive: Bool = false,
|
|
named tableName: String,
|
|
columns: [String]? = nil,
|
|
request: some SQLSubqueryable,
|
|
type: RowDecoder.Type)
|
|
{
|
|
self.cte = SQLCTE(
|
|
tableName: tableName,
|
|
columns: columns,
|
|
sqlSubquery: request.sqlSubquery,
|
|
isRecursive: recursive)
|
|
}
|
|
}
|
|
|
|
extension CommonTableExpression {
|
|
/// Creates a common table expression from a request.
|
|
///
|
|
/// For example:
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player) ...
|
|
/// let p = CommonTableExpression<Void>(
|
|
/// named: "p",
|
|
/// request: Player.all())
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player) ...
|
|
/// let p = CommonTableExpression<Void>(
|
|
/// named: "p",
|
|
/// request: SQLRequest<Player>(sql: "SELECT * FROM player"))
|
|
///
|
|
/// - parameter recursive: Whether this common table expression needs a
|
|
/// `WITH RECURSIVE` sql clause.
|
|
/// - parameter tableName: The table name of the common table expression.
|
|
/// - parameter columns: The columns of the common table expression. If nil,
|
|
/// the columns are the columns of the request.
|
|
/// - parameter request: A request.
|
|
public init(
|
|
recursive: Bool = false,
|
|
named tableName: String,
|
|
columns: [String]? = nil,
|
|
request: some SQLSubqueryable)
|
|
{
|
|
self.init(
|
|
recursive: recursive,
|
|
named: tableName,
|
|
columns: columns,
|
|
request: request,
|
|
type: RowDecoder.self)
|
|
}
|
|
|
|
/// Creates a common table expression from an SQL string and
|
|
/// optional arguments.
|
|
///
|
|
/// For example:
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player WHERE name = 'O''Brien') ...
|
|
/// let p = CommonTableExpression<Void>(
|
|
/// named: "p",
|
|
/// sql: "SELECT * FROM player WHERE name = ?",
|
|
/// arguments: ["O'Brien"])
|
|
///
|
|
/// - parameter recursive: Whether this common table expression needs a
|
|
/// `WITH RECURSIVE` sql clause.
|
|
/// - parameter tableName: The table name of the common table expression.
|
|
/// - parameter columns: The columns of the common table expression. If nil,
|
|
/// the columns are the columns of the request.
|
|
/// - parameter sql: An SQL string.
|
|
/// - parameter arguments: Statement arguments.
|
|
public init(
|
|
recursive: Bool = false,
|
|
named tableName: String,
|
|
columns: [String]? = nil,
|
|
sql: String,
|
|
arguments: StatementArguments = StatementArguments())
|
|
{
|
|
self.init(
|
|
recursive: recursive,
|
|
named: tableName,
|
|
columns: columns,
|
|
request: SQLRequest(sql: sql, arguments: arguments),
|
|
type: RowDecoder.self)
|
|
}
|
|
|
|
/// Creates a common table expression from an SQL *literal*.
|
|
///
|
|
/// ``SQL`` literals allow you to safely embed raw values in your SQL,
|
|
/// without any risk of syntax errors or SQL injection:
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player WHERE name = 'O''Brien') ...
|
|
/// let name = "O'Brien"
|
|
/// let p = CommonTableExpression<Void>(
|
|
/// named: "p",
|
|
/// literal: "SELECT * FROM player WHERE name = \(name)")
|
|
///
|
|
/// - parameter recursive: Whether this common table expression needs a
|
|
/// `WITH RECURSIVE` sql clause.
|
|
/// - parameter tableName: The table name of the common table expression.
|
|
/// - parameter columns: The columns of the common table expression. If nil,
|
|
/// the columns are the columns of the request.
|
|
/// - parameter sqlLiteral: An ``SQL`` literal.
|
|
public init(
|
|
recursive: Bool = false,
|
|
named tableName: String,
|
|
columns: [String]? = nil,
|
|
literal sqlLiteral: SQL)
|
|
{
|
|
self.init(
|
|
recursive: recursive,
|
|
named: tableName,
|
|
columns: columns,
|
|
request: SQLRequest(literal: sqlLiteral),
|
|
type: RowDecoder.self)
|
|
}
|
|
}
|
|
|
|
extension CommonTableExpression<Row> {
|
|
/// Creates a common table expression from a request.
|
|
///
|
|
/// For example:
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player) ...
|
|
/// let p = CommonTableExpression(
|
|
/// named: "p",
|
|
/// request: Player.all())
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player) ...
|
|
/// let p = CommonTableExpression(
|
|
/// named: "p",
|
|
/// request: SQLRequest<Player>(sql: "SELECT * FROM player"))
|
|
///
|
|
/// - parameter recursive: Whether this common table expression needs a
|
|
/// `WITH RECURSIVE` sql clause.
|
|
/// - parameter tableName: The table name of the common table expression.
|
|
/// - parameter columns: The columns of the common table expression. If nil,
|
|
/// the columns are the columns of the request.
|
|
/// - parameter request: A request.
|
|
public init(
|
|
recursive: Bool = false,
|
|
named tableName: String,
|
|
columns: [String]? = nil,
|
|
request: some SQLSubqueryable)
|
|
{
|
|
self.init(
|
|
recursive: recursive,
|
|
named: tableName,
|
|
columns: columns,
|
|
request: request,
|
|
type: Row.self)
|
|
}
|
|
|
|
/// Creates a common table expression from an SQL string and
|
|
/// optional arguments.
|
|
///
|
|
/// For example:
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player WHERE name = 'O''Brien') ...
|
|
/// let p = CommonTableExpression(
|
|
/// named: "p",
|
|
/// sql: "SELECT * FROM player WHERE name = ?",
|
|
/// arguments: ["O'Brien"])
|
|
///
|
|
/// - parameter recursive: Whether this common table expression needs a
|
|
/// `WITH RECURSIVE` sql clause.
|
|
/// - parameter tableName: The table name of the common table expression.
|
|
/// - parameter columns: The columns of the common table expression. If nil,
|
|
/// the columns are the columns of the request.
|
|
/// - parameter sql: An SQL string.
|
|
/// - parameter arguments: Statement arguments.
|
|
public init(
|
|
recursive: Bool = false,
|
|
named tableName: String,
|
|
columns: [String]? = nil,
|
|
sql: String,
|
|
arguments: StatementArguments = StatementArguments())
|
|
{
|
|
self.init(
|
|
recursive: recursive,
|
|
named: tableName,
|
|
columns: columns,
|
|
request: SQLRequest(sql: sql, arguments: arguments),
|
|
type: Row.self)
|
|
}
|
|
|
|
/// Creates a common table expression from an SQL *literal*.
|
|
///
|
|
/// ``SQL`` literals allow you to safely embed raw values in your SQL,
|
|
/// without any risk of syntax errors or SQL injection:
|
|
///
|
|
/// // WITH p AS (SELECT * FROM player WHERE name = 'O''Brien') ...
|
|
/// let name = "O'Brien"
|
|
/// let p = CommonTableExpression(
|
|
/// named: "p",
|
|
/// literal: "SELECT * FROM player WHERE name = \(name)")
|
|
///
|
|
/// - parameter recursive: Whether this common table expression needs a
|
|
/// `WITH RECURSIVE` sql clause.
|
|
/// - parameter tableName: The table name of the common table expression.
|
|
/// - parameter columns: The columns of the common table expression. If nil,
|
|
/// the columns are the columns of the request.
|
|
/// - parameter sqlLiteral: An ``SQL`` literal.
|
|
public init(
|
|
recursive: Bool = false,
|
|
named tableName: String,
|
|
columns: [String]? = nil,
|
|
literal sqlLiteral: SQL)
|
|
{
|
|
self.init(
|
|
recursive: recursive,
|
|
named: tableName,
|
|
columns: columns,
|
|
request: SQLRequest(literal: sqlLiteral),
|
|
type: Row.self)
|
|
}
|
|
}
|
|
|
|
extension CommonTableExpression {
|
|
var relationForAll: SQLRelation {
|
|
.all(fromTable: tableName)
|
|
}
|
|
|
|
/// Creates a request for all rows of the common table expression.
|
|
///
|
|
/// You can fetch from this request:
|
|
///
|
|
/// // WITH answer AS (SELECT 42 AS value)
|
|
/// // SELECT * FROM answer
|
|
/// struct Answer: Decodable, FetchableRecord {
|
|
/// var value: Int
|
|
/// }
|
|
/// let cte = CommonTableExpression<Answer>(
|
|
/// named: "answer",
|
|
/// sql: "SELECT 42 AS value")
|
|
/// let answer = try cte.all().with(cte).fetchOne(db)!
|
|
/// print(answer.value) // prints 42
|
|
///
|
|
/// You can embed this request as a subquery:
|
|
///
|
|
/// // WITH answer AS (SELECT 42 AS value)
|
|
/// // SELECT * FROM player
|
|
/// // WHERE score = (SELECT * FROM answer)
|
|
/// let answer = CommonTableExpression(
|
|
/// named: "answer",
|
|
/// sql: "SELECT 42 AS value")
|
|
/// let players = try Player
|
|
/// .filter(Column("score") == answer.all())
|
|
/// .with(answer)
|
|
/// .fetchAll(db)
|
|
public func all() -> QueryInterfaceRequest<RowDecoder> {
|
|
QueryInterfaceRequest(relation: relationForAll)
|
|
}
|
|
|
|
/// An SQL expression that checks the inclusion of an expression in a
|
|
/// common table expression.
|
|
///
|
|
/// let playerNameCTE = CommonTableExpression(
|
|
/// named: "playerName",
|
|
/// request: Player.select(Column("name"))
|
|
///
|
|
/// // name IN playerName
|
|
/// playerNameCTE.contains(Column("name"))
|
|
public func contains(_ element: some SQLExpressible) -> SQLExpression {
|
|
SQLCollection.table(tableName).contains(element.sqlExpression)
|
|
}
|
|
}
|
|
|
|
/// A low-level common table expression
|
|
struct SQLCTE {
|
|
/// The table name of the common table expression.
|
|
var tableName: String
|
|
|
|
/// The columns of the common table expression.
|
|
///
|
|
/// When nil, the CTE selects the columns of the request:
|
|
///
|
|
/// -- Columns a, b
|
|
/// WITH t AS (SELECT 1 AS a, 2 AS b) ...
|
|
///
|
|
/// When not nil, `columns` provides the columns of the CTE:
|
|
///
|
|
/// -- Column id
|
|
/// WITH t(id) AS (SELECT 1) ...
|
|
/// ~~
|
|
var columns: [String]?
|
|
|
|
/// The common table expression subquery.
|
|
///
|
|
/// WITH t AS (SELECT ...)
|
|
/// ~~~~~~~~~~
|
|
var sqlSubquery: SQLSubquery
|
|
|
|
/// Whether this common table expression needs a `WITH RECURSIVE`
|
|
/// sql clause.
|
|
var isRecursive: Bool
|
|
|
|
/// The number of columns in the common table expression.
|
|
func columnCount(_ db: Database) throws -> Int {
|
|
if let columns {
|
|
// No need to hit the database
|
|
return columns.count
|
|
}
|
|
|
|
do {
|
|
return try sqlSubquery.columnCount(db)
|
|
} catch let error as DatabaseError where error.resultCode == .SQLITE_ERROR {
|
|
// Maybe the CTE refers to other CTEs: https://github.com/groue/GRDB.swift/issues/1275
|
|
// We can't modify the CTE request by creating or extending the
|
|
// WITH clause with other CTEs, because we'd need to parse SQL.
|
|
// So let's rewrite the error message, and guide the user towards
|
|
// a more precise CTE definition:
|
|
let message = [
|
|
[
|
|
"""
|
|
Can't compute the number of columns in the \
|
|
\(String(reflecting: tableName)) common table expression
|
|
""",
|
|
error.message,
|
|
].compactMap { $0 }.joined(separator: ": "),
|
|
"""
|
|
Check the syntax of the SQL definition, or provide the \
|
|
explicit list of selected columns with the `columns` parameter \
|
|
in the CommonTableExpression initializer.
|
|
""",
|
|
].joined(separator: ". ")
|
|
throw DatabaseError(
|
|
resultCode: error.extendedResultCode,
|
|
message: message,
|
|
sql: error.sql,
|
|
arguments: error.arguments,
|
|
publicStatementArguments: error.publicStatementArguments)
|
|
}
|
|
}
|
|
}
|
|
|
|
extension CommonTableExpression {
|
|
/// Creates an association to a common table expression that you can join
|
|
/// or include in another request.
|
|
///
|
|
/// The key of the returned association is the table name of the common
|
|
/// table expression.
|
|
///
|
|
/// - parameter cte: A common table expression.
|
|
/// - parameter condition: A function that returns the joining clause.
|
|
/// - parameter left: A `TableAlias` for the left table.
|
|
/// - parameter right: A `TableAlias` for the right table.
|
|
/// - returns: An association to the common table expression.
|
|
public func association<Destination>(
|
|
to cte: CommonTableExpression<Destination>,
|
|
on condition: @escaping (_ left: TableAlias, _ right: TableAlias) -> any SQLExpressible)
|
|
-> JoinAssociation<RowDecoder, Destination>
|
|
{
|
|
JoinAssociation(
|
|
to: cte.relationForAll,
|
|
condition: .expression { condition($0, $1).sqlExpression })
|
|
}
|
|
|
|
/// Creates an association to a common table expression that you can join
|
|
/// or include in another request.
|
|
///
|
|
/// The key of the returned association is the table name of the common
|
|
/// table expression.
|
|
///
|
|
/// - parameter cte: A common table expression.
|
|
/// - returns: An association to the common table expression.
|
|
public func association<Destination>(
|
|
to cte: CommonTableExpression<Destination>)
|
|
-> JoinAssociation<RowDecoder, Destination>
|
|
{
|
|
JoinAssociation(to: cte.relationForAll, condition: .none)
|
|
}
|
|
|
|
/// Creates an association to a table record that you can join
|
|
/// or include in another request.
|
|
///
|
|
/// The key of the returned association is the table name of `Destination`.
|
|
///
|
|
/// - parameter destination: The record type at the other side of
|
|
/// the association.
|
|
/// - parameter condition: A function that returns the joining clause.
|
|
/// - parameter left: A `TableAlias` for the left table.
|
|
/// - parameter right: A `TableAlias` for the right table.
|
|
/// - returns: An association to the common table expression.
|
|
public func association<Destination>(
|
|
to destination: Destination.Type,
|
|
on condition: @escaping (_ left: TableAlias, _ right: TableAlias) -> any SQLExpressible)
|
|
-> JoinAssociation<RowDecoder, Destination>
|
|
where Destination: TableRecord
|
|
{
|
|
JoinAssociation(
|
|
to: Destination.relationForAll,
|
|
condition: .expression { condition($0, $1).sqlExpression })
|
|
}
|
|
|
|
/// Creates an association to a table record that you can join
|
|
/// or include in another request.
|
|
///
|
|
/// The key of the returned association is the table name of `Destination`.
|
|
///
|
|
/// - parameter destination: The record type at the other side of
|
|
/// the association.
|
|
/// - returns: An association to the common table expression.
|
|
public func association<Destination>(
|
|
to destination: Destination.Type)
|
|
-> JoinAssociation<RowDecoder, Destination>
|
|
where Destination: TableRecord
|
|
{
|
|
JoinAssociation(to: Destination.relationForAll, condition: .none)
|
|
}
|
|
|
|
/// Creates an association to a table that you can join
|
|
/// or include in another request.
|
|
///
|
|
/// The key of the returned association is the table name of `Destination`.
|
|
///
|
|
/// - parameter destination: The table at the other side of the association.
|
|
/// - parameter condition: A function that returns the joining clause.
|
|
/// - parameter left: A `TableAlias` for the left table.
|
|
/// - parameter right: A `TableAlias` for the right table.
|
|
/// - returns: An association to the common table expression.
|
|
public func association<Destination>(
|
|
to destination: Table<Destination>,
|
|
on condition: @escaping (_ left: TableAlias, _ right: TableAlias) -> any SQLExpressible)
|
|
-> JoinAssociation<RowDecoder, Destination>
|
|
{
|
|
JoinAssociation(
|
|
to: destination.relationForAll,
|
|
condition: .expression { condition($0, $1).sqlExpression })
|
|
}
|
|
|
|
/// Creates an association to a table that you can join
|
|
/// or include in another request.
|
|
///
|
|
/// The key of the returned association is the table name of `Destination`.
|
|
///
|
|
/// - parameter destination: The table at the other side of the association.
|
|
/// - returns: An association to the common table expression.
|
|
public func association<Destination>(
|
|
to destination: Table<Destination>)
|
|
-> JoinAssociation<RowDecoder, Destination>
|
|
{
|
|
JoinAssociation(to: destination.relationForAll, condition: .none)
|
|
}
|
|
}
|