record

问题 I have a set of records: type Person = { Name : string Age : int } let oldPeople = set [ { Name = "The Doctor"; Age = 1500 }; { Name = "Yoda"; Age = 900 } ] Unlike the hardcoded example above, the set of data actually comes from a data source (over which I have very little control). Now I need to subtract a set of data from another data source. In general, the data in this second source matches, but occasionally there is a difference in captialization: let peopleWhoAreConfusedAboutTheirAge =

问题 I have two tables, user and role, one user can have more than 1 role user: ID | FIRSTNAME | LASTNAME | etc.. 1 | PETER | Blomp | role: ID | ROLEID | USERID (which is user ID) 70 | 5 | 1 (peter) 71 | 2 | 1 What I have to do and cant figure out is, how can retrieve data of users whos roleid is not even to some integer, for. ex. user PETER can have roleID's 5 and 2, what i am trying to get is that IF Peter has roleid 3, he excludes from resultset, no matter if he has roleid 5. 回答1: SELECT user

问题 I have a table Id|Parent|Counter --|------|------- 1| A | NULL 2| A | NULL 3| A | NULL 4| B | NULL 5| B | NULL 6| C | NULL 7| D | NULL 8| D | NULL I want to update the table such that the counter column is update (+1) as long as previous parent = parent . If not, counter =1 so: Id|Parent|Counter --|------|------- 1| A | 1 2| A | 2 3| A | 3 4| B | 1 5| B | 2 6| C | 1 7| D | 1 8| D | 2 I have about 3.5M records. I can get a select query but can get it to work with update. This is what I have:

问题 I want to create a record field of type byte array with 8 elements but couldn't figure out the correct syntax. I did something like: let dataRecord = { id : int data : byte array } let dataValues : byte array = Array.zeroCreate 8 let myArray = { id = 0; data = dataValues } Can it be done in the record definition? How? My example, above, seemed to work but I don't know if it is safe or the best or most correct way. 回答1: There's nothing wrong with what you're currently doing (other than that

问题 I am trying to create a record which uses one of the previously defined fields to calculate the value of another, within the same constructor. e.g. myRecordType = {Foo:int; Bar:int[]} myRecord = {Foo = 5; Bar = Array.init Foo (fun i -> i)} When I try this it doesn't recognise Foo as already existing. I also can't reference Foo using myRecord.Foo , but that makes sense since myRecord hasn't been constructed yet. However I would've thought that Foo and Bar would be in the same scope, so Bar

问题 As I am new to mysql, let me clear this doubt. how to write a query to find/select the latest added records only? Example: Consider a Table, which is daily added certain amount of records. Now the table contain 1000 records. And the total 1000 records are taken out for some performance. After sometimes table is added 100 records. Now I would like take the remain 100 only from the 1100 to do some operation. How to do it? (For example only, I have given the numbers, But originally I don't know

问题 Is there a compiler implementation reason why records can't have the AllowNullLiteralAttribute attribute or is this a chosen constraint? I do see this constraint force cleaner code sometimes but not always. [<AllowNullLiteralAttribute>] type IBTreeNode = { mutable left : IBTreeNode; mutable right : IBTreeNode; mutable value : int} with member this.Insert x = if x < this.value then if this.left = null then this.left <- {left = null; right = null; value = x} else this.left.Insert x else if this

问题 I have tried a lot of things out there: red5, jquery webcam, html5 ... but none of these solution record a video and leave it ready to upload to a server. Is there anyway (html5, flash, whatever ... the better cross-broswer solution, the best) to upload video (+ audio!) and upload the result to a server (I guess through AJAX) ? Summarize: jQueryWebcam (https://github.com/infusion/jQuery-webcam): it has flash video, uploads to a server image, not a video Eric Bidelman's solution (http:/

问题 I need to know, first and foremost, if what I'm trying to do is even possible. If it is possible, I then need to know how. It's far easier to demonstrate the problem rather than explain it so here goes: I have an "Enhanced Record" (the purpose - though not important to this question - is to produce a "Smart String" type, to replace the normal String type): TLKString = record Value: String; // Some methods here to operate on and build String values // Allows me to assign String values directly

问题 in Android it's currently impossible to record system-audio with the Android-SDK. Therefore I played around a bit with TinyALSA (since Android 4) and hope I can reroute the audio-out so I can record it. When I call "tinymix" on my device I get following configuration: ctl type num name value 0 ENUM 1 DL1 Equalizer Flat response 1 ENUM 1 DL2 Left Equalizer 450Hz High-pass 2 ENUM 1 DL2 Right Equalizer 450Hz High-pass 3 ENUM 1 Sidetone Equalizer Flat response 4 ENUM 1 AMIC Equalizer High-pass