将app从SQLite.swift转换为GRDB.swift第二个问题

Question

我正在继续将我的一些应用程序从SQLite.sift转换到GRDB.swift。我将我的结构转换为添加Codable，FetchableRecord，这样它们就可以更好地与GRDB一起工作。这是在回复我关于这个主题的第一篇文章时提出的。

struct FigureList: Codable, FetchableRecord
{
    let figID: Int64
    var notes: String?
    var theDescription: String
    var obrienNum: String
    var manufNum: String?
    var catagory: String?
}

这是我正在寻找帮助来重做的代码片段，这样它就可以与GRDB一起工作了。我的应用程序使用这种类型的代码从数据库表构建数组。相当标准的流程。

static func getFigureList() -> [FigureList]
{
    var theArray = [FigureList]()
    let theTable = Table(gTheCollection)

    let figID = Expression<Int64>("FigureID")
    let notes = Expression<String>("Notes")
    let theDescription = Expression<String>("theDescription")
    let obrienNum = Expression<String>("ObrienNum")
    let manufNum = Expression<String>("ManufNum")
    let theCatagory = Expression<String>("Category")

    do {
        for figures in try Database.shared.databaseConnection!.prepare(theTable.order(obrienNum)) {

            theArray.append(FigureList(figID: figures[figID],
                                       notes: figures[notes],
                                       theDescription: figures[theDescription],
                                       obrienNum: figures[obrienNum],
                                       manufNum: figures[manufNum],
                                       catagory: figures[theCatagory]))
        }
    } catch {
        print("Fetching figure list failed: \(error)")
    }
    return theArray
}

这就是我到目前为止想出的。它不会产生任何警告或错误，但我很确定它不是完全正确的。再次，提前感谢您的帮助。

static func getFigList() -> [FigureList]
{
    var theArray = [FigureList]()
    let theTable = gTheCollection
    
    let figID = Column("FigureID")
    let notes = Column("Notes")
    let theDescription = Column("theDescription")
    let obrienNum = Column("ObrienNum")
    let manufNum = Column("ManufNum")
    let theCatagory = Column("Category")
    
    do {
        try Database.shared.databaseConnection!.read { db in
            let figures = try Row.fetchOne(db, sql: "SELECT * FROM = ? ORDER BY ObrienNum", arguments: [theTable])
            
            theArray.append(FigureList.init(figID: figures![figID],
                                            notes: figures![notes],
                                            theDescription: figures![theDescription],
                                            obrienNum: figures![obrienNum],
                                            manufNum: figures![manufNum],
                                            catagory: figures![theCatagory]))
        }
    } catch {
        print("Fetching figure list failed: \(error)")
    }
    
    return theArray
}

Answer 1

我将我的结构转换为Codable，FetchableRecord，这样它们就可以更好地与

一起工作。

好的。现在很简单了：

static func getFigList() throws -> [FigureList] {
    return try Database.shared.databaseConnection!.read { db in
        // SELECT * FROM FigureList ORDER BY ObrienNum
        return FigureList.order(Column("ObrienNum")).fetchAll(db)
    }
}