Shulou(Shulou.com)06/01 Report--

This article mainly introduces how to store and read pictures in mysql database, which has certain reference value and can be used for reference by friends who need it. I hope you will learn a lot after reading this article. Next, let the editor take you to learn about it.

Mysql stores the method of reading a picture: first, converts the picture into a buffer stream; then obtains the byte array of the picture and performs related operations; finally, it reads the picture through "public void MapSearchQuery (out byte [] imageByteResulet) {.}".

First, introduce the mysql-related data types: there are four BLOB types in MySQL, TinyBlob (maximum 255Byte), Blob (maximum 65K), MediunBlob (16m), and LongBlob (maximum 4G). Note here that if the relevant Data too long... appears in your database The word may be that the size of the category you have chosen is not enough.

Next, I will briefly explain why I did not use the path to store the picture, but instead stored the picture directly in MySQL. There are two reasons:

1. You don't need a lot of pictures, a database only needs one picture.

2, the software structure is to access the following affiliated clients by a master client through WebService. If the attached client does not store pictures for direct access by the main client, then the main client is bound to need a function to load pictures (similar to the function of FTP).

Let's go straight to the code:

Public bool MapSearchWrite (string strImagePath) {/ / convert the picture into a buffer stream FileStream fs = new FileStream (strImagePath, FileMode.Open, FileAccess.Read); / / get the byte array of the picture byte [] byImage = new byte [fs.Length]; fs.Read (byImage, 0, byImage.Length); fs.Close () / / Database connection MySqlConnection conn = new MySqlConnection (); conn.ConnectionString = "Server=localhost;Uid=root;Password=123456;Database=firefighting;charset=gb2312"; try {conn.Open ();} catch {conn.Close (); conn.Dispose () Throw new ArgumentException ("failed to connect to the map retrieval database");} / / determine whether there are records in the database string strQueryCmd = "select PicNum from images"; MySqlCommand cmdQuery = new MySqlCommand (strQueryCmd, conn); MySqlDataReader dataReader = cmdQuery.ExecuteReader (); / / execute operation MySqlCommand cmd = new MySqlCommand () If (dataReader.Read ()) {cmd.CommandText = "update images set Image=@byImage";} else {cmd.CommandText = "insert into images (Image) values (@ byImage)";} cmd.CommandType = CommandType.Text Cmd.Parameters.Add ("@ byImage", MySqlDbType.MediumBlob); cmd.Parameters [0] .value = byImage; cmd.Connection = conn; int affectedRows = 0; try {affectedRows = cmd.ExecuteNonQuery ();} catch {affectedRows =-1 } / / close connection and other cmd.Dispose (); conn.Close (); conn.Dispose (); if (affectedRows)

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