Postgresql: UUID的使用

方法1：使用create extension命令

win7需要通过管理员权限打开pgAdmin，输入命令：

create extension "uuid-ossp"

安装扩展成功以后，就可以通过uuid_generate_v4()或uuid_generate_v1()查询



方法2：

默认安装的 Postgresql 是不带 UUID 函数的，为了生成一个 UUID，我们不得不在客户端生成。其实在 Postgresql 的安装目录下已经存在这样的函数定义，我们只需将其 import 进来即可。

在安装目录的 share/contrib 下面，可以找到 uuid-ossp.sql，使用以下命令：

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psql -d pisces -U postgres -f D:/Service/PostgreSQL/9.0/share/contrib/uuid-ossp.sql

参数说明：

-d: 数据库名

-U: 用户名

-f: 要import的文件

以下截屏说明导入正确：



然后我们可以尝试用导入的函数生成一个UUID：

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select uuid_generate_v4();



更多uuid函数，请在postgresql文档中搜索：

uuid-ossp

在C#中使用uuid类型的例子：

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//---------------------------------------------------------------------------

// <copyright file="Program.cs" company="Xinsoft.org">

// Copyright (c) Yaping Xin. All rights reserved.

// </copyright>

// <Description>Entry class for the testing.</Description>

//---------------------------------------------------------------------------

namespace Org.Xinsoft.Demo.Postgresql

{

using System;

using System.Data;

using Npgsql;

/// <summary>

/// Entry class for the testing.

/// </summary>

internal class TestUuidProgram

{

/// <summary>

/// Entry point for the testing.

/// </summary>

/// <param name="args">console arguments</param>

internal static void Main(string[] args)

{

using (DatabaseOperation db = new DatabaseOperation())

{

db.OpenConnection();

Console.WriteLine(db.ConnState);

string sql = "insert into demotable(id, name) values(@id, @name);";

using (Npgsql.NpgsqlCommand command = db.Connection.CreateCommand())

{

command.CommandText = sql;

command.CommandType = CommandType.Text;

command.Parameters.Add("@id", NpgsqlTypes.NpgsqlDbType.Uuid);

command.Parameters.Add("@name", NpgsqlTypes.NpgsqlDbType.Varchar, 25);

command.Prepare();

for (int i = 0; i < 10; i++)

{

command.Parameters[0].Value = Guid.NewGuid();

command.Parameters[1].Value = string.Format("{0} {1}", i, DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff"));

int effects = command.ExecuteNonQuery();

Console.WriteLine(string.Format("INSERT: {0} rows effected.", effects));

}

}

sql = "select id, name from demotable;";

using (Npgsql.NpgsqlCommand command = db.Connection.CreateCommand())

{

command.CommandText = sql;

command.CommandType = CommandType.Text;

command.Prepare();

DataTable result = DatabaseHelper.GetDataTable(command.ExecuteReader());

int rows = result.Rows.Count;

int cols = result.Columns.Count;

Console.WriteLine("Rows: {0}", rows);

for (int i = 0; i < cols; i++)

{

Console.WriteLine("Column[{0}]: {1}/t| {2}", i, result.Columns[i].ColumnName, result.Columns[i].DataType.Name);

}

Console.WriteLine("Query result:");

for (int i = 0; i < rows; i++)

{

DataRow row = result.Rows[i];

for (int j = 0; j < cols; j++)

{

Console.Write("{0}/t", row[j].ToString());

}

Console.WriteLine(string.Empty);

}

}

sql = "delete from demotable;";

using (Npgsql.NpgsqlCommand command = db.Connection.CreateCommand())

{

command.CommandText = sql;

command.CommandType = CommandType.Text;

int effects = command.ExecuteNonQuery();

Console.WriteLine(string.Format("DELETE: {0} rows effected.", effects));

}

db.CloseConnection();

}

}

}

}

上述例子用到的表结构如下：

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CREATE TABLE demotable

(

id uuid NOT NULL,

"name" character varying(25),

CONSTRAINT pk_demotable PRIMARY KEY (id)

)

WITH (

OIDS=FALSE

);

ALTER TABLE demotable OWNER TO agentusr;

方法2引用：http://blog.csdn.net/yapingxin/article/details/6365055