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POTransfer a MySQL table into a F# matrix
 

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    <p>I would like to transfer a SQL table (let say i. 2 columns : one containing users ID and one containing users age and ii. n rows) containing only integers into a F# matrix (same dimensions). I manage to do so with the following F# code, but I am convinced it is not the most efficient way to do so.</p> <p>Indeed, the only way I found to dimensionate the F# matrix was to create 2 tables with a single value (number of rows and number of columns respectively) using MySQL and transfer these value into F#.</p> <p>Is it possible to import a mySQL table into a F# matrix with a F# code which "recognize" the dimension of the matrix. Basically I would like a function which take a table address as an argument and return a matrix.</p> <p>Here is my code : </p> <pre><code>#r "FSharp.PowerPack.dll" #r "Microsoft.Office.Interop.Excel" open System open System.Data open System.Data.SqlClient open Microsoft.Office.Interop open Microsoft.FSharp.Math open System.Collections.Generic //Need of three types : User, number of rows and number of columns type user = { ID : int; Age : int;} type nbrRows = {NbreL : int ;} type nbrCol = {NbreC : int ;} // I. Import the SQL data into F# // I.1. Import the number of rows of the table into F# let NbrRows = seq { use cnn = new SqlConnection(@"myconnection; database=MyDataBase; integrated security=true") use cmd1 = new SqlCommand("Select * from theTablesWhichContainsTheNumberOfRows", cnn) cnn.Open() use reader = cmd1.ExecuteReader() while reader.Read() do yield { NbreL = unbox(reader.["Expr1"]) } } let NbrRowsList = NbrRows |&gt; Seq.toList // convert the sequence into a List // I.2. Same code to import the number of columns of the table let NbrCol = seq { use cnn = new SqlConnection(@"MyConnection; database=myDatabase; integrated security=true") use cmd1 = new SqlCommand("Select * from theTablesWhichContainsTheNumberOfColumns", cnn) cnn.Open() use reader = cmd1.ExecuteReader() while reader.Read() do yield { NbreC = unbox(reader.["Expr1"]) } } let NbrColsList = NbrCol |&gt; Seq.toList // Initialisation of the Matrix let matrixF = Matrix.create NbrRowsList.[0].NbreL NbrColsList.[0].NbreC 0. //Transfer of the mySQL User table into F# through a sequence as previously let GetUsers = seq { use cnn = new SqlConnection(@"myConnection, database=myDatabase; integrated security=true") use cmd = new SqlCommand("Select * from tableUser ORDER BY ID", cnn) cnn.Open() use reader = cmd.ExecuteReader() while reader.Read() do yield { ID = unbox(reader.["ID"]) Age = unbox(reader.["Age"]) } } // Sequence to list let UserDatabaseList = GetUsers |&gt; Seq.toList // Fill of the user matrix for i in 0 .. (NbrRowList.[0].NbreL - 1) do matrixF.[0,i] &lt;- UserDatabaseList.[i].ID |&gt; float matrixF.[1,i] &lt;- UserDatabaseList.[i].Age|&gt; float matrixUsers </code></pre>
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