ASP.NET下向SQLServer2008导入文件实例操作方法
在Microsoft SQL Server2008以后的版本中,将删除image数据类型。在新的开发工作中将不适用此数据类型,并打算修改当前使用此数据类型的应用程序,改用varbinary(max)数据类型。
ASP.NET向SQL Server导入文件主要用到FileUpload控件的FileBytes属性。该属性从FileUpload控件所指定的文件返回一个字节数组 。
1.数据库准备
为了方便大家能够理解,这里我们只设计两个字段,一个是文件类型字段,字段名为FileType,另一个是存放文件内容字段,字段名为FileContent。创建数据库
,数据库名为VarFile,语句如下:
CREATE DATABASE VARFILE
GO
创建表,表名为FileInOut,语句如下:
USE VARFILE
GO
CREATE TABLE FILEINTOU
(
FileType nvarchar(30) not null,
FileContent varbinary(max) null
)
2.添加控件
运行VS2008并新建一个网站,在页面Default.aspx中添加一个FileUpload控件,ID 为FileUpload1.同时添加三个Button按钮,ID分别为fileUp和fileLoad。Text属性分别设置为“上传文件”和“下载文件”。
3.添加代码
(1)添加命名空间,因为和SQL Server数据库连接,所以添加using System.Data.Sqlclient和using System.Data命名空间。又因为要设置输出流的HTTP的字符集为"gb2312"字符编码,所以添加using System.Text命名空间。同时又因为要把导出文件强类型化为字符串,所以添加using System.Collections.Specialized命名空间。
(2)添加“上传文件”按钮的事件代码。当单击“上传文件”按钮后,获取FileUpload控件所选择的文件的文件类型以及文件的字节数组插入数据库中。切换到设计视图,双击“上传文件”按钮,添加"上传文件"按钮事件代码,代码如下:
代码如下:
protected void fileUp_Click(object sender,EventArgs e)
{
if(FileUpload1.FileName==string.Empty)
{
Response.Write("<script>altert(‘请选择要上传的文件')</script>");
return;
}
string mailto:connstr=@%22Data Source=69F638102711447\SQL2008;Initial Catalog=VarFile;Integrated Security=Ture"; //数据库连接字符串
string the Selected=FileUpload1.FileName; //获取上传文件的后缀名
string extension=theSelected.Substring(theSelected.LastIndexOf(".")).ToLower();
if(CheckFileType(extension)) //如果有指定的文件类型
{
string contentType=GetContentType(extension);
string sqlstr="insert into FileInOut values(@FileType,@FileCount)"; //上传文件的SQL语句
string sqlstrclear="truncate table FileInOut"; //清空数据库SQL语句
SqlConnection con=new SqlConnection(connstr); //实例化数据库连接对象
SqlCommand cmd=new SqlCommand(sqlstr,con); //实例化上传文件SQL命令
SqlCommand cmdclear=new SqlCommand(sqlstrclear,con); //实例化清空数据库SQL命令
//定义问价类型参数
cmd.Parameters.Add(new SqlParameter("@FileType”,SlqDbType.NvarChar,30));
cmd.Parameters["@FileType"].Value=contentType; //定义文件内容参数
cmd.Parameters.Add(new SqlParameter("@FileCount",SqlDbType.NVarChar,30)); //将文件转化为字节数组作为@FileCount的值
cmd.Parameters["@FileCount"].Value=FileUpload1.FileBytes;
con.Open();
cmdclear.ExecuteNonQuery(); //执行清空数据库命令
cmd.ExecuteNonQuery(); //执行上传文件命令
}
}
(3)添加获取文件类型和获得文件导出方式的函数方法。首先查看所要上传文件类型是否在指定问价类型内,如果在,则可以直接导入文件,然后根据文件类型
获取此文件导出方式并存放在FileType字段中,代码如下:
代码如下:
public static bool CheckFileType(string type)
{
StringDictionary sd=new StringDictionary(); //实例化集合StringDictionary类
sd.Add(".doc","application/msword");
sd.Add(".ppt","application/vnd.ms-powerpoint");
sd.Add(".xsl","application/vnd.ms-excel");
sd.Add(".rtf","application/msword");
sd.Add(".html","text/html");
sd.Add(".htm","text/html");
sd.Add(".txt","text/plain");
sd.Add(".pdf","application/pdf");
return sd.ContainsKey(type); //确定StringDictionary是否包含特定键
}
public static string GetContentType(string extension) //获取输出文件方式
{StringDictionary sd=new StringDictionary();
sd.Add(".doc","application/msword");
sd.Add(".ppt","application/vnd.ms-powerpoint");
sd.Add(".xsl","application/vnd.ms-excel");
sd.Add(".rtf","application/msword");
sd.Add(".html","text/html");
sd.Add(".htm","text/html");
sd.Add(".txt","text/plain");
sd.Add(".pdf","application/pdf");
return sd[extension]; //返回对应键的值
}
(4)上传文件,选择一个pdf文件,单击"上传文件"按钮后,打开数据库中的FileInOut表,如图所示可以看到。

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

Full table scanning may be faster in MySQL than using indexes. Specific cases include: 1) the data volume is small; 2) when the query returns a large amount of data; 3) when the index column is not highly selective; 4) when the complex query. By analyzing query plans, optimizing indexes, avoiding over-index and regularly maintaining tables, you can make the best choices in practical applications.

InnoDB's full-text search capabilities are very powerful, which can significantly improve database query efficiency and ability to process large amounts of text data. 1) InnoDB implements full-text search through inverted indexing, supporting basic and advanced search queries. 2) Use MATCH and AGAINST keywords to search, support Boolean mode and phrase search. 3) Optimization methods include using word segmentation technology, periodic rebuilding of indexes and adjusting cache size to improve performance and accuracy.

Yes, MySQL can be installed on Windows 7, and although Microsoft has stopped supporting Windows 7, MySQL is still compatible with it. However, the following points should be noted during the installation process: Download the MySQL installer for Windows. Select the appropriate version of MySQL (community or enterprise). Select the appropriate installation directory and character set during the installation process. Set the root user password and keep it properly. Connect to the database for testing. Note the compatibility and security issues on Windows 7, and it is recommended to upgrade to a supported operating system.

The difference between clustered index and non-clustered index is: 1. Clustered index stores data rows in the index structure, which is suitable for querying by primary key and range. 2. The non-clustered index stores index key values and pointers to data rows, and is suitable for non-primary key column queries.

MySQL is an open source relational database management system. 1) Create database and tables: Use the CREATEDATABASE and CREATETABLE commands. 2) Basic operations: INSERT, UPDATE, DELETE and SELECT. 3) Advanced operations: JOIN, subquery and transaction processing. 4) Debugging skills: Check syntax, data type and permissions. 5) Optimization suggestions: Use indexes, avoid SELECT* and use transactions.

MySQL supports four index types: B-Tree, Hash, Full-text, and Spatial. 1.B-Tree index is suitable for equal value search, range query and sorting. 2. Hash index is suitable for equal value searches, but does not support range query and sorting. 3. Full-text index is used for full-text search and is suitable for processing large amounts of text data. 4. Spatial index is used for geospatial data query and is suitable for GIS applications.

In MySQL database, the relationship between the user and the database is defined by permissions and tables. The user has a username and password to access the database. Permissions are granted through the GRANT command, while the table is created by the CREATE TABLE command. To establish a relationship between a user and a database, you need to create a database, create a user, and then grant permissions.

MySQL and MariaDB can coexist, but need to be configured with caution. The key is to allocate different port numbers and data directories to each database, and adjust parameters such as memory allocation and cache size. Connection pooling, application configuration, and version differences also need to be considered and need to be carefully tested and planned to avoid pitfalls. Running two databases simultaneously can cause performance problems in situations where resources are limited.
