SQLSpecificExpressible

SQLSpecificExpressible is a protocol for all database-specific types that can be turned into an SQL expression. Types whose existence is not purely dedicated to the database should adopt the SQLExpressible protocol instead.

For example, Column is a type that only exists to help you build requests, and it adopts SQLSpecificExpressible.

On the other side, Int adopts SQLExpressible.

SQLExpressible

SQL Ordering Support

SQL Selection Support

  • forKey(_:) Extension method

    Returns an aliased column.

    For example:

    // SELECT (width * height) AS area FROM shape
let area = (Column("width") * Column("height")).forKey("area")
let request = Shape.select(area)
if let row = try Row.fetchOne(db, request) {
    let area: Int = row["area"]
}

    If you need to refer to the aliased column in another part of a request, use Column(...).detached. For example:

    // SELECT (width * height) AS area FROM shape ORDER BY area
let area = (Column("width") * Column("height")).forKey("area")
let request = Shape
    .select(area)
    .order(Column("area").detached)
let rows = try Row.fetchCursor(db, request)
while let row = try rows.next() {
    let area: Int = row["area"]
}

SQL Collations Support

  • collating(_:) Extension method

    Returns a collated expression.

    For example:

    Player.filter(Column("email").collating(.nocase) == "contact@example.com")

Like Operator

  • like(_:escape:) Extension method

    An SQL expression with the LIKE SQL operator.

    // email LIKE '%@example.com"
Column("email").like("%@example.com")

// title LIKE '%10\%%' ESCAPE '\'
Column("title").like("%10\\%%", escape: "\\")