1.数据库表
-- 创建文件表
create table tb_file
(
id number(20) not null,
file_name nvarchar2(100),
file_content blob,
constraint pk_tb_file primary key (id)
)
tablespace mydb storage(
initial 64K
minextents 1
maxextents unlimited
);
--设置tb_file主键自增
create sequence seq_tb_file --创建自增序列
minvalue 1
maxvalue 9999999999999999999
start with 1
increment by 1
nocache
order;
create or replace trigger ai_tb_file --创建触发器，当插入新记录时自增主键id
before insert on tb_file
for each row
when (new.id is null)
begin
select seq_tb_file.nextval into :new.id from dual;
end;
2 在数据库中保存和读取二进制文件
//添加命名空间
using System;
using System.Data.OracleClient;
using System.IO;
using System.Data;
/// <summary>
/// 把文件插入数据库中
/// </summary>
/// <param name="filePath">文件名，包含路径，如c:temp.rar</param>
/// <returns></returns>
public int Insert(string filePath)
{
string connStr = "data source=orcl;user=mydbuser;password=mydbuser;";
OracleConnection conn = new OracleConnection(connStr);
OracleCommand cmd = conn.CreateCommand();
//读取文件
FileStream fs = File.OpenRead(filePath);
byte[] buffer = new byte[fs.Length];
fs.Read(buffer, 0, buffer.Length);
OracleParameter paramFileContent = cmd.CreateParameter();
paramFileContent.OracleType = OracleType.Blob;
paramFileContent.ParameterName = "FileContent";
paramFileContent.Direction = ParameterDirection.Input;
paramFileContent.Value = buffer;
cmd.Parameters.Add(paramFileContent);
OracleParameter paramFileName = cmd.CreateParameter();
paramFileName.OracleType = OracleType.VarChar;
paramFileName.ParameterName = "FileName";
paramFileName.Direction = ParameterDirection.Input;
paramFileName.Value = Path.GetFileName(filePath);
cmd.Parameters.Add(paramFileName);
string sqlInsert = "insert into tb_file (file_name, file_content) values (:FileName, :FileContent)";
cmd.CommandText = sqlInsert;
cmd.CommandType = CommandType.Text;
conn.Open();
int result = cmd.ExecuteNonQuery();
conn.Close();
return result;
}
/// <summary>
/// 根据文件名从数据库中获取文件
/// </summary>
/// <param name="fileName">数据库中的文件名</param>
/// <param name="savePath">文件的保存路径，包括文件名，如c:file.rar</param>
public void Select(string fileName, string savePath)
{
string connStr = "data source=orcl;user=mydbuser;password=mydbuser;";
OracleConnection conn = new OracleConnection(connStr);
OracleCommand cmd = conn.CreateCommand();
string sqlSelect = "select file_name, file_content from tb_file where file_name=:FileName";
cmd.CommandText = sqlSelect;
cmd.CommandType = CommandType.Text;
OracleParameter paramFileName = cmd.CreateParameter();
paramFileName.OracleType = OracleType.VarChar;
paramFileName.ParameterName = "FileName";
paramFileName.Direction = ParameterDirection.Input;
paramFileName.Value = fileName;
cmd.Parameters.Add(paramFileName);
conn.Open();
OracleDataReader dr = cmd.ExecuteReader();
dr.Read();
byte[] buffer = (byte[])dr["file_content"];
dr.Close();
conn.Close();
//把文件保存到指定路径
File.WriteAllBytes(savePath, buffer);
}
