数据库连接字符串

VBA编程中的数据库连接与操作详解VBA（Visual Basic for Applications）是一种用于编写Microsoft Office 应用程序的编程语言。

在VBA编程中，与数据库的连接和操作是非常重要的一部分。

本文将详细介绍VBA编程中的数据库连接和操作，并提供一些实例来帮助读者更好地理解。

一、数据库连接1. 连接字符串数据库连接通常需要使用连接字符串来指定数据库的位置和其他连接参数。

连接字符串的格式取决于所使用的数据库类型。

下面是一些常见数据库的连接字符串示例：- Access数据库：Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\myFolder\myDatabase.accdb;Persist SecurityInfo=False;- SQL Server数据库：Provider=SQLOLEDB;DataSource=serverName;Initial Catalog=databaseName;UserID=userName;Password=password;- MySQL数据库：Driver={MySQL ODBC 5.3Driver};Server=serverAddress;Database=databaseName;User=user ;Password=password;Option=3;需要注意，以上示例中的连接字符串仅供参考，实际使用时应根据具体情况进行修改。

2. 打开连接在VBA中，可以使用ADODB（ActiveX Data Objects）对象来进行数据库操作。

首先需要创建一个ADODB.Connection 对象，并使用连接字符串来打开连接。

下面是一个示例：```vbaDim conn As ObjectSet conn = CreateObject("ADODB.Connection")conn.ConnectionString ="Provider=Microsoft.ACE.OLEDB.12.0;DataSource=C:\myFolder\myDatabase.accdb;Persist SecurityInfo=False;"conn.Open```在打开连接之前，可以根据需要设置连接对象的其他属性，如CommandTimeout（执行命令的超时时间）和CursorLocation（指定游标的位置）等。

一、介绍SQLite数据库SQLite是一种轻量级的关系型数据库管理系统，它包含在一个相对小的C库中。

SQLite主要用途是在嵌入式设备上使用，例如移动通联方式、PDA、MP3播放器以及其他一些类型的嵌入式系统。

它可以使用SQL语言进行数据操作，包括创建表、查找数据、更新数据和删除数据等。

二、SQLite连接字符串在使用SQLite数据库时，连接字符串是非常重要的。

连接字符串是用来连接数据库服务器并指定要连接的数据库的一种字符串。

SQLite连接字符串有两种类型：绝对路径和相对路径。

本文将重点探讨SQLite 连接字符串的相对路径。

1. 相对路径的概念相对路径是指文件或目录相对于当前工作目录的路径。

在SQLite连接字符串中，相对路径表示数据库文件相对于应用程序的路径。

相对路径的好处是方便移植应用程序，只需将数据库文件与应用程序放在同一目录下即可。

2. 相对路径的使用在SQLite连接字符串中，使用相对路径需要注意以下几点：a. 相对路径的表示方式相对路径可以使用"."表示当前目录，".."表示上一级目录，以及其他相对位置的路径表示方式。

"./data.db"表示当前目录下的data.db文件，"../data/data.db"表示上一级目录下的data文件夹中的data.db文件。

b. 应用程序的当前工作目录应用程序的当前工作目录是指应用程序在执行时所处的目录。

在使用相对路径时，需要确保应用程序的当前工作目录与数据库文件所在的目录一致，否则连接会失败。

c. 设置当前工作目录可以使用操作系统提供的函数或方法来设置应用程序的当前工作目录，以确保正确使用相对路径。

在C#中可以使用Environment.CurrentDirectory属性来设置当前工作目录，在Java中可以使用System.setProperty("user.dir", "path")来设置当前工作目录。

数据库连接池的连接字符串写法在 中，连接字符串是用来建立与数据库之间的连接的关键元素。

连接字符串的写法取决于你使用的数据库类型和数据库引擎。

以下是一个示例连接字符串，用于连接到Microsoft SQL Server 数据库的连接池：```Imports System.Data.SqlClientModule Module1Sub Main()Dim connectionString As String = "Data Source=YourServerName;Initial Catalog=YourDatabaseName;User ID=YourUsername;Password=YourPassword;Integrated Security=False;Max Pool Size=100;Pooling=True;"Dim connection As New SqlConnection(connectionString)Tryconnection.Open()' 连接已经打开，可以执行数据库操作Console.WriteLine("Connected to SQL Server")Catch ex As ExceptionConsole.WriteLine("Error: " & ex.Message)Finallyconnection.Close()End TryEnd SubEnd Module```在这个示例中，你需要替换`YourServerName`、`YourDatabaseName`、`YourUsername` 和`YourPassword` 分别为你的SQL Server 的实际信息。

`Max Pool Size` 和`Pooling` 是用于配置连接池的选项，它们指定了连接池的最大大小和是否启用连接池。

MySQL中的连接字符串和连接选项配置在数据库应用程序中，连接到数据库是一个重要的步骤，连接字符串和连接选项配置是实现这一步骤的关键。

MySQL作为一种流行的关系型数据库管理系统（RDBMS），提供了丰富的连接字符串和连接选项配置功能，使得开发人员能够更好地控制和管理数据库连接。

连接字符串是用于指定数据库连接的字符串参数，包括数据库的地址、端口号、用户名、密码等信息。

连接选项配置是一组用于优化和调整数据库连接行为的参数，包括连接池大小、读写超时时间、字符编码等设置。

本文将详细介绍MySQL中连接字符串和连接选项配置的相关知识，希望能够帮助读者更好地理解和应用。

一、连接字符串连接字符串是用于指定数据库连接的字符串参数，它可以根据实际需求来设置不同的参数，以满足不同的数据库连接使用场景。

常见的连接字符串包括以下几个部分：1. 数据库地址数据库地址是指数据库服务器的地址和端口号，格式为"host:port"。

例如，localhost:3306表示连接到本地MySQL服务器的默认端口。

2. 用户名和密码用户名和密码是用于数据库身份验证的凭据，格式为"username:password"。

例如，root:123456表示使用用户名root和密码123456进行身份验证。

3. 数据库名称数据库名称是指要连接的数据库的名称，格式为"dbname"。

例如，mydatabase表示连接到名为mydatabase的数据库。

4. 字符编码字符编码是指数据库中存储的字符数据的编码格式，常用的编码格式包括UTF-8、GBK等。

可以通过设置字符编码来确保数据的正确存储和读取。

5. 其他可选参数除了上述基本参数外，连接字符串还可以包含其他可选参数，用于进一步优化和调整数据库连接行为。

例如，可以设置连接超时时间、读写超时时间、连接池大小等参数。

二、连接选项配置连接选项配置是一组用于优化和调整数据库连接行为的参数，可以通过连接字符串的方式进行配置。

C#数据库连接字符串⽂章转载⾄：sa登陆："Data Source=.;Initial Catalog=数据库;User ID=sa,pwd=;";windows登陆Data Source=.;Initial Catalog=数据库;Integrated Security=Truec#数据库连接字符串集合(⼀)常⽤连接:1.使⽤SqlConnection对象:a. Sql 验证public void SqlConnectionOpen(){SqlConnection conn= new SqlConnection();conn.ConnectionString = "user id=sa;password=;initial catalog=northwind;datasource=localhost;connect Timeout=20";conn.Open();}b. Windows ⾝份验证public void SqlConnectionOpen(){SqlConnection conn= new SqlConnection();conn.ConnectionString = "Integrated Security=SSPI；initial catalog=northwind;datasource=localhost;connect Timeout=20";conn.Open();}2.使⽤OleDbConnection对象:public void OleDBConnectionOpen(){OleDBConnection conn = new OleDbconnection();conn.ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;DataSource=C:\Customer.mdb";conn.Open();}(⼆)其它:1.ODBC连接Access本地数据库conGoodDay.Open("Driver={Microsoft Access Driver(*.mdb)};"+"Dbq=C:\a.mdb;"+"Uid=Admin;"+"Pwd=;");2.ODBC连接Access系统数据库conGoodDay.Open("Driver={Microsoft Access Driver(*.mdb)};"+"Dbq=C:\a.mdb;"+"SystemDB=Admin;"+"Pwd=;");3.ODBC连接Access系统数据库conGoodDay.Open("Driver={Microsoft Access Driver(*.mdb)};"+"Dbq=\\server\share\a.mdb;");4.ODBC连接Excel系统数据库conGoodDay.Open("Driver={Microsoft Access Driver(*.xls)};"+"DriverId=790;"+"Dbq=C:\a.xls;"+"DefaultDir=c:\somepath;");5.ODBC连接Oracle系统数据库conGoodDay.Open("Driver={Microsoft ODBC for oracle};"+"Server=OracleServer.world;"+"Uid=Admin;"+"Pwd=password;");6.ODBC连接Sql ServrconGoodDay.Open("Driver={Sql Server};"+"Server=myServer;"+"Database=myDatabaseName;""Uid=Admin;"+"Pwd=password;");7.ODBC连接Visual FoxProconGoodDay.Open("Driver={Microsoft Visual FoxPro Driver};"+"SourceType=DBC;"+"SourceDB=c:a.dbc;"+"Exclusive=No;");Windows ⾝份验证建议使⽤ Windows ⾝份验证（有时也称为“集成安全性”）连接到⽀持其的数据源。

（最全的数据库连接字符串）connectionstringPS:如果不是太稳定的数据库，最好使用connection lifetime=10来限制连接池内连接的生存日期转自SQL ServerODBCStandard Security:"Driver={SQLServer};Server=Aron1;Database=pubs;Uid=sa;Pwd=asdasd;"Trusted connection:"Driver={SQLServer};Server=Aron1;Database=pubs;Trusted_Connection=yes;"Prompt for username and password:oConn.Properties("Prompt") = adPromptAlwaysoConn.Open "Driver={SQL Server};Server=Aron1;DataBase=pubs;"OLE DB, OleDbConnection (.NET)Standard Security:"Provider=sqloledb;Data Source=Aron1;Initial Catalog=pubs;User Id=sa;Password=asdasd;"Trusted Connection:"Provider=sqloledb;Data Source=Aron1;Initial Catalog=pubs;Integrated Security=SSPI;"(use serverName\instanceName as Data Source to use an specifik SQLServer instance, only SQLServer2000)Prompt for username and password:oConn.Provider = "sqloledb"oConn.Properties("Prompt") = adPromptAlwaysoConn.Open "Data Source=Aron1;Initial Catalog=pubs;"Connect via an IP address:"Provider=sqloledb;DataSource=190.190.200.100,1433;NetworkLibrary=DBMSSOCN;Initial Catalog=pubs;User ID=sa;Password=asdasd;"(DBMSSOCN=TCP/IP instead of Named Pipes, at the end of the Data Source is the port to use (1433 is the default))SqlConnection (.NET)Standard Security:"Data Source=Aron1;Initial Catalog=pubs;User Id=sa;Password=asdasd;"- or -"Server=Aron1;Database=pubs;UserID=sa;Password=asdasd;Trusted_Connection=False"(both connection strings produces the same result)Trusted Connection:"Data Source=Aron1;Initial Catalog=pubs;Integrated Security=SSPI;"- or -"Server=Aron1;Database=pubs;Trusted_Connection=True;"(both connection strings produces the same result)(use serverName\instanceName as Data Source to use an specifik SQLServer instance, only SQLServer2000)Connect via an IP address:"Data Source=190.190.200.100,1433;Network Library=DBMSSOCN;Initial Catalog=pubs;User ID=sa;Password=asdasd;"(DBMSSOCN=TCP/IP instead of Named Pipes, at the end of the Data Source is the port to use (1433 is the default))Declare the SqlConnection:C#:using System.Data.SqlClient;SqlConnection oSQLConn = new SqlConnection(); oSQLConn.ConnectionString="my connection string"; oSQLConn.Open();:Imports System.Data.SqlClientDim oSQLConn As SqlConnection = New SqlConnection() oSQLConn.ConnectionString="my connection string" oSQLConn.Open()Data ShapeMS Data Shape"Provider=MSDataShape;Data Provider=SQLOLEDB;Data Source=Aron1;Initial Catalog=pubs;User ID=sa;Password=asdasd;"Want to learn data shaping? Check out 4GuyfFromRolla's great article about Data Shaping >>Read moreHow to define which network protocol to useExample:"Provider=sqloledb;DataSource=190.190.200.100,1433;NetworkLibrary=DBMSSOCN;Initial Catalog=pubs;User ID=sa;Password=asdasd;"Name Network librarydbnmpntw Win32 Named Pipesdbmssocn Win32 Winsock TCP/IPdbmsspxn Win32 SPX/IPXdbmsvinn Win32 Banyan Vinesdbmsrpcn Win32 Multi-Protocol (Windows RPC)Important note!When connecting through the SQLOLEDB provider use the syntax Network Library=dbmssocnand when connecting through MSDASQL provider use the syntax Network=dbmssocnAll SqlConnection connection string propertiesThis table shows all connection string properties for the SqlConnection object. Most of the properties are also used in ADO. All properties and descriptions is from msdn.Name Default DescriptionApplication Name The name of the application, or '.Net SqlClient Data Provider' if no application name is provided.AttachDBFilename-or-extended properties-or-Initial File Name The name of the primary file, including the full path name, of an attachable database. The database name must be specified with the keyword 'database'.Connect Timeout-or-Connection Timeout 15 The length of time (in seconds) to wait for a connection to the server before terminating the attempt and generating an error.Connection Lifetime 0 When a connection is returned to the pool, its creation time is compared with the current time, and the connection is destroyed if that time span (in seconds) exceeds the value specified by connection lifetime. Useful in clustered configurations to force load balancing between a running server and a server just brought on-line.Connection Reset 'true' Determines whether the database connection is reset when being removed from the pool. Setting to 'false' avoids making an additional server round-trip when obtaining a connection, but the programmer must be aware thatthe connection state is not being reset.Current Language The SQL Server Language record name.Data Source-or-Server-or-Address-or-Addr-or-Network Address The name or network address of the instance of SQL Server to which to connect.Enlist 'true' When true, the pooler automatically enlists the connection in the creation thread's current transaction context.Initial Catalog-or-Database The name of the database.Integrated Security-or-Trusted_Connection 'false' Whether the connection is to be a secure connection or not. Recognized values are 'true', 'false', and 'sspi', which is equivalent to 'true'.Max Pool Size 100 The maximum number of connections allowed in the pool.Min Pool Size 0 The minimum number of connections allowed in the pool.Network Library-or-Net 'dbmssocn' The network library used to establish a connection to an instance of SQL Server. Supported values include dbnmpntw (Named Pipes), dbmsrpcn (Multiprotocol), dbmsadsn (Apple Talk), dbmsgnet (VIA), dbmsipcn (Shared Memory) and dbmsspxn (IPX/SPX), and dbmssocn (TCP/IP).The corresponding network DLL must be installed on the system to which you connect. If you do not specify a network and you use a local server (for example, "." or "(local)"), shared memory is used.Packet Size 8192 Size in bytes of the network packets used to communicate with an instance of SQL Server.Password-or-Pwd The password for the SQL Server account logging on.Persist Security Info 'false' When set to 'false', security-sensitive information, such as the password, is not returned as part of the connection if the connection is open or has ever been in an open state. Resetting the connection string resets all connection string values including the password.Pooling 'true' When true, the SQLConnection object is drawn from the appropriate pool, or if necessary, is created and added to the appropriate pool.User ID The SQL Server login account.Workstation ID the local computer name The name of the workstation connecting to SQL Server.NoteUse ; to separate each property.If a name occurs more than once, the value from the last one in the connection string will be used.If you are building your connection string in your app using values from user input fields, make sure the user can't change the connection string by inserting an additional property with another value within the user value.SQL Server 2005SQL Native Client ODBC DriverStandard security:"Driver={SQL Native Client};Server=Aron1;Database=pubs;UID=sa;PWD=asdasd;"Trusted connection:"Driver={SQL Native Client};Server=Aron1;Database=pubs;Trusted_Connection=yes;"EquivalentsIntegrated Security=SSPI equals Trusted_Connection=yesPrompt for username and password:oConn.Properties("Prompt") = adPromptAlwaysoConn.Open "Driver={SQL Native Client};Server=Aron1;DataBase=pubs;"Enabling MARS (multiple active result sets):"Driver={SQL Native Client};Server=Aron1;Database=pubs;Trusted_Connection=yes; MARS_Connection=yes"EquivalentsMultipleActiveResultSets=true equals MARS_Connection=yesUsing MARS with SQL Native Client, by Chris Lee >>Encrypt data sent over network:"Driver={SQL Native Client};Server=Aron1;Database=pubs;Trusted_Connection=yes;E ncrypt=yes"Attach a database file on connect to a local SQL Server Express instance:"Driver={SQL Native Client};Server=.\SQLExpress;AttachDbFilename=c:\asd\qwe\myd bfile.mdf;Database=dbname;Trusted_Connection=Yes;"- or -"Driver={SQL Native Client};Server=.\SQLExpress;AttachDbFilename=|DataDirectory| mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;"(use |DataDirectory| when your database file resides in the data directory)Why is the "Database" parameter needed? Answer: If the database was previously attached, SQL Server does not reattach it (it uses the attached database as the default for the connection).Download the SQL Native Client here >> (the package contains booth the ODBC driver and the OLE DB provider)Using SQL Server 2005 Express? Don't miss the server name syntax: SERVERNAME\SQLEXPRESS (Substitute "SERVERNAME" with the name of the computer)SQL Native Client OLE DB ProviderStandard security:"Provider=SQLNCLI;Server=Aron1;Database=pubs;UID=sa;P WD=asdasd;"Trusted connection:"Provider=SQLNCLI;Server=Aron1;Database=pubs;Trusted_ Connection=yes;"EquivalentsIntegrated Security=SSPI equals Trusted_Connection=yesPrompt for username and password:oConn.Properties("Prompt") = adPromptAlwaysoConn.Open"Provider=SQLNCLI;Server=Aron1;DataBase=pubs;"Enabling MARS (multiple active result sets):"Provider=SQLNCLI;Server=Aron1;Database=pubs;Trusted_Connection=yes;MarsConn=yes"EquivalentsMarsConn=yes equals MultipleActiveResultSets=true equals MARS_Connection=yesUsing MARS with SQL Native Client, by Chris Lee >>Encrypt data sent over network:"Provider=SQLNCLI;Server=Aron1;Database=pubs;Trusted_ Connection=yes;Encrypt=yes"Attach a database file on connect to a local SQL Server Express instance:"Provider=SQLNCLI;Server=.\SQLExpress;AttachDbFilename =c:\asd\qwe\mydbfile.mdf;Database=dbname;Trusted_Connecti on=Yes;"- or -"Provider=SQLNCLI;Server=.\SQLExpress;AttachDbFilename =|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Conn ection=Yes;"(use |DataDirectory| when your database file resides in thedata directory)Why is the "Database" parameter needed? Answer: If the database was previously attached, SQL Server does not reattach it (it uses the attached database as the default for the connection).Download the SQL Native Client here >> (the package contains booth the ODBC driver and the OLE DB provider)Using SQL Server 2005 Express? Don't miss the server name syntax: SERVERNAME\SQLEXPRESS (Substitute "SERVERNAME" with the name of the computer)SqlConnection (.NET)Standard Security:"Data Source=Aron1;Initial Catalog=pubs;User Id=sa;Password=asdasd;"- or -"Server=Aron1;Database=pubs;UserID=sa;Password=asdasd;Trusted_Connection=False"(both connection strings produces the same result)Trusted Connection:"Data Source=Aron1;Initial Catalog=pubs;Integrated Security=SSPI;"- or -"Server=Aron1;Database=pubs;Trusted_Connection=True;"(both connection strings produces the same result)(use serverName\instanceName as Data Source to use an specifik SQLServer instance)Connect via an IP address:"Data Source=190.190.200.100,1433;Network Library=DBMSSOCN;Initial Catalog=pubs;User ID=sa;Password=asdasd;"(DBMSSOCN=TCP/IP instead of Named Pipes, at the end of the Data Source is the port to use (1433 is the default))Enabling MARS (multiple active result sets):"Server=Aron1;Database=pubs;Trusted_Connection=True;M ultipleActiveResultSets=true"Note! Use 2.0 for MARS functionality. MARS is not supported in 1.0 nor 1.1Streamline your Data Connections by Moving to MARS, by Laurence Moroney, >>Attach a database file on connect to a local SQL Server Express instance:"Server=.\SQLExpress;AttachDbFilename=c:\asd\qwe\mydb file.mdf;Database=dbname;Database=dbname;Trusted_Connect ion=Yes;"- or -"Server=.\SQLExpress;AttachDbFilename=|DataDirectory|m ydbfile.mdf;Database=dbname;Trusted_Connection=Yes;"(use |DataDirectory| when your database file resides in the data directory)Why is the "Database" parameter needed? Answer: If the database was previously attached, SQL Server does not reattach it (it uses the attached database as the default for the connection).Using "User Instance" on a local SQL Server Express instance:"Data Source=.\SQLExpress;integrated security=true;attachdbfilename=|DataDirectory|\mydb.mdf;user instance=true;"The "User Instance" functionality creates a new SQL Server instance on the fly during connect. This works only on a local SQL Server 2005 instance and only when connecting using windows authentication over local named pipes. The purpose is to be able to create a full rights SQL Server instance to a user with limited administrative rights on the computer. To enable the functionality: sp_configure 'user instances enabled','1' (0 to disable)Using SQL Server 2005 Express? Don't miss the server name syntax: SERVERNAME\SQLEXPRESS (Substitute "SERVERNAME" with the name of the computer)Context Connection - connecting to "self" from within your CLR stored prodedure/functionC#:using(SqlConnection connection = new SqlConnection("context connection=true")){connection.Open();// Use the connection}Visual Basic:Using connection as new SqlConnection("context connection=true")connection.Open()' Use the connectionEnd UsingThe context connection lets you execute Transact-SQL statements in the same context (connection) that your code was invoked in the first place.Read moreWhen to use SQL Native Client?.Net applicationsDo not use the SQL Native Client. Use the .NET Framework Data Provider for SQL Server (SqlConnection).COM applications, all other then .NET applicationsUse the SQL Native Client if you are accessing an SQL Server 2005 and need the new features of SQL Server 2005 such as MARS, encryption, XML data type etc. Continue use your current provider (OLE DB / ODBC through the MDAC package) if you are not connecting to an SQL Server 2005 (that's quite obvious eh..) or if you are connecting to an SQL Server 2005 but are not using any of the new SQL Server 2005 features.For more details on the differences between MDAC and SQL Native Client, read this msdn article >>AccessODBCStandard Security:"Driver={Microsoft Access Driver (*.mdb)};Dbq=C:\mydatabase.mdb;Uid=Admin;Pwd=;"Workgroup:"Driver={Microsoft Access Driver (*.mdb)};Dbq=C:\mydatabase.mdb;SystemDB=C:\mydatabase.m dw;"Exclusive:"Driver={Microsoft Access Driver (*.mdb)};Dbq=C:\mydatabase.mdb;Exclusive=1;Uid=admin;Pwd ="OLE DB, OleDbConnection (.NET)Standard security:"Provider=Microsoft.Jet.OLEDB.4.0;DataSource=\somepath\mydb.mdb;User Id=admin;Password=;"Workgroup (system database):"Provider=Microsoft.Jet.OLEDB.4.0;DataSource=\somepath\mydb.mdb;Jet OLEDB:System Database=system.mdw;"With password:"Provider=Microsoft.Jet.OLEDB.4.0;DataSource=\somepath\mydb.mdb;Jet OLEDB:Database Password=MyDbPassword;"OracleODBCNew version:"Driver={Microsoft ODBC for Oracle};Server=OracleServer.world;Uid=Username;Pwd=asdasd; "Old version:"Driver={Microsoft ODBC Driver for Oracle};ConnectString=OracleServer.world;Uid=myUsername;Pw d=myPassword;"OLE DB, OleDbConnection (.NET)Standard security:"Provider=msdaora;Data Source=MyOracleDB;User Id=UserName;Password=asdasd;"This one's from Microsoft, the following are from OracleStandard Security:"Provider=OraOLEDB.Oracle;Data Source=MyOracleDB;User Id=Username;Password=asdasd;"Trusted Connection:"Provider=OraOLEDB.Oracle;DataSource=MyOracleDB;OSAuthent=1;"OracleConnection (.NET)Standard:"Data Source=MyOracleDB;Integrated Security=yes;"This one works only with Oracle 8i release 3 or laterSpecifying username and password:"Data Source=MyOracleDB;User Id=username;Password=passwd;Integrated Security=no;"This one works only with Oracle 8i release 3 or laterDeclare the OracleConnection:C#:using System.Data.OracleClient;OracleConnection oOracleConn = new OracleConnection();oOracleConn.ConnectionString = "my connection string";oOracleConn.Open();:Imports System.Data.OracleClientDim oOracleConn As OracleConnection = New OracleConnection()oOracleConn.ConnectionString = "my connection string"oOracleConn.Open()Missing the System.Data.OracleClient namespace? Download .NET Managed Provider for Oracle >>Great article! "Features of Oracle Data Provider for .NET" by Rama Mohan G. at C# CornerCore Labs OraDirect (.NET)Standard:"User ID=scott; Password=tiger; Host=ora; Pooling=true; Min Pool Size=0;Max Pool Size=100; Connection Lifetime=0"Read more at Core Lab and the product page.Data ShapeMS Data Shape:"Provider=MSDataShape.1;Persist Security Info=False;Data Provider=MSDAORA;Data Source=orac;user id=username;password=mypw"Want to learn data shaping? Check out 4GuyfFromRolla's great article about Data Shaping >>MySQLMyODBCMyODBC 2.50 Local database:"Driver={mySQL};Server=localhost;Option=16834;Database =mydatabase;"MyODBC 2.50 Remote database:"Driver={mySQL};Server=;Port=3306;Optio n=131072;Stmt=;Database=my-database;Uid=username;Pwd=password;"MyODBC 3.51 Local database:"DRIVER={MySQL ODBC 3.51 Driver};SERVER=localhost;DATABASE=myDatabase;USER=myUs ername;PASSWORD=myPassword;OPTION=3;"MyODBC 3.51 Remote database:"DRIVER={MySQL ODBC 3.51 Driver};SERVER=;PORT=3306;DATABASE=myD atabase;USER=myUsername;PASSWORD=myPassword;OPTION=3;"OLE DB, OleDbConnection (.NET)Standard:"Provider=MySQLProv;Data Source=mydb;User Id=UserName;Password=asdasd;"Connector/Net 1.0 (.NET)Standard:"Server=Server;Database=Test;Uid=UserName;Pwd=asdasd ;"Download the driver at MySQL Developer Zone.Specifying port:"Server=Server;Port=1234;Database=Test;Uid=UserName;P wd=asdasd;"Default port is 3306. Enter value -1 to use a named pipe connection.Declare the MySqlClient connection:C#:using MySql.Data.MySqlClient;MySqlConnection oMySqlConn = new MySqlConnection();oMySqlConn.ConnectionString = "Server=Server;Database=Test;Uid=UserName;Pwd=asdasd;";oMySqlConn.Open();:Imports MySql.Data.MySqlClientDim oMySqlConn As MySqlConnection = New MySqlConnection()oMySqlConn.ConnectionString = "Server=Server;Database=Test;Uid=UserName;Pwd=asdasd;"oMySqlConn.Open()MySqlConnection (.NET)eInfoDesigns.dbProvider:"Data Source=server;Database=mydb;User ID=username;Password=pwd;Command Logging=false"This one is used with eInfoDesigns dbProvider, an add-on to .NETDeclare the MySqlConnection:C#:using eInfoDesigns.dbProvider.MySqlClient;MySqlConnection oMySqlConn = new MySqlConnection();oMySqlConn.ConnectionString = "my connection string";oMySqlConn.Open();:Imports eInfoDesigns.dbProvider.MySqlClientDim oMySqlConn As MySqlConnection = New MySqlConnection()oMySqlConn.ConnectionString = "my connection string"oMySqlConn.Open()SevenObjects MySqlClient (.NET)Standard:"Host=server; UserName=myusername; Password=mypassword;Database=mydb;"This is a freeware data provider from SevenObjectsCore Labs MySQLDirect (.NET)Standard:"User ID=root; Password=pwd; Host=localhost; Port=3306; Database=test;Direct=true; Protocol=TCP; Compress=false; Pooling=true; Min Pool Size=0;Max Pool Size=100; Connection Lifetime=0"Read more at Core Lab and the product page.InterbaseODBC, EasysoftLocal computer:"Driver={Easysoft IB6 ODBC};Server=localhost;Database=localhost:C:\mydatabase.gd b;Uid=username;Pwd=password"Remote Computer:"Driver={Easysoft IB6 ODBC};Server=ComputerName;Database=ComputerName:C:\m ydatabase.gdb;Uid=username;Pwd=password"Read more about this driver: Easysoft ODBC-Interbase driver >>ODBC, IntersolvLocal computer:"Driver={INTERSOLV InterBase ODBC Driver (*.gdb)};Server=localhost;Database=localhost:C:\mydatabase.gd b;Uid=username;Pwd=password"Remote Computer:"Driver={INTERSOLV InterBase ODBC Driver (*.gdb)};Server=ComputerName;Database=ComputerName:C:\ mydatabase.gdb;Uid=username;Pwd=password"This driver are provided by DataDirect Technologies >> (formerly Intersolv)OLE DB, SIBPROviderStandard:"provider=sibprovider;location=localhost:;datasource=c:\databases\gdbs\mygdb.gdb;userid=SYSDBA;password=masterkey"Specifying character set:"provider=sibprovider;location=localhost:;datasource=c:\databases\gdbs\mygdb.gdb;userid=SYSDBA;password=masterkey;character set=ISO8859_1"Specifying role:"provider=sibprovider;location=localhost:;datasource=c:\databases\gdbs\mygdb.gdb;userid=SYSDBA;password=masterkey;role=DIGITADORES"Read more about SIBPROvider >>Read more about connecting to Interbase in this Borland Developer Network articleIBM DB2OLE DB, OleDbConnection (.NET) from msTCP/IP:"Provider=DB2OLEDB;Network TransportLibrary=TCPIP;Network Address=XXX.XXX.XXX.XXX;Initial Catalog=MyCtlg;Package Collection=MyPkgCol;Default Schema=Schema;User ID=MyUser;Password=MyPW"APPC:"Provider=DB2OLEDB;APPC Local LU Alias=MyAlias;APPC Remote LU Alias=MyRemote;Initial Catalog=MyCtlg;Package Collection=MyPkgCol;Default Schema=Schema;User ID=MyUser;Password=MyPW"IBM's OLE DB Provider (shipped with IBM DB2 UDB v7 or above)TCP/IP:Provider=IBMDADB2;Database=sample;HOSTNAME=db2h ost;PROTOCOL=TCPIP;PORT=50000;uid=myUserName;pwd=my Pwd;ODBCStandard:"driver={IBM DB2 ODBC DRIVER};Database=myDbName;hostname=myServerName;port =myPortNum;protocol=TCPIP; uid=myUserName; pwd=myPwd"SybaseODBCStandard Sybase System 12 (or 12.5) Enterprise Open Client:"Driver={SYBASE ASE ODBC Driver};Srvr=Aron1;Uid=username;Pwd=password"Standard Sybase System 11:"Driver={SYBASE SYSTEM 11};Srvr=Aron1;Uid=username;Pwd=password;Database=mydb "For more information check out the Adaptive ServerEnterprise Document SetsIntersolv 3.10:"Driver={INTERSOLV 3.10 32-BIT Sybase};Srvr=Aron1;Uid=username;Pwd=password;"Sybase SQL Anywhere (former Watcom SQL ODBC driver):"ODBC; Driver=Sybase SQL Anywhere 5.0; DefaultDir=c:\dbfolder\;Dbf=c:\mydatabase.db;Uid=username;P wd=password;Dsn="""""Note! The two double quota following the DSN parameter at the end are escaped quotas (VB syntax), you may have to change this to your language specific escape syntax. The empty DSN parameter is indeed critical as not including it will result in error 7778.Read more in the Sybase SQL Anywhere User Guide (see part 3, chapter 13) >>OLE DBAdaptive Server Anywhere (ASA):"Provider=ASAProv;Data source=myASA"Read more in the ASA User Guide (part 1, chapter 2) >>Adaptive Server Enterprise (ASE) with Data Source .IDS file:"Provider=Sybase ASE OLE DB Provider; Data source=myASE"Note that you must create a Data Source .IDS file using the Sybase Data Administrator. These .IDS files resemble ODBC DSNs.Adaptive Server Enterprise (ASE):"Provider=Sybase.ASEOLEDBProvider;Srvr=myASEserver,50 00;Catalog=myDBname;UserId=username;Password=password"- some reports on problem using the above one, try the following as an alternative -"Provider=Sybase.ASEOLEDBProvider;ServerName=myASEserver,5000;Initial Catalog=myDBname;User Id=username;Password=password"This one works only from Open Client 12.5 where the server port number feature works,燼llowing fully qualified connection strings to be used without defining燼ny .IDS Data Source files.AseConnection (.NET)Standard:"DataSource='myASEserver';Port=5000;Database='myDBname';UID=' username';PWD='password';"Declare the AseConnection:C#:using Sybase.Data.AseClient;AseConnection oCon = new AseConnection();oCon.ConnectionString="my connection string";oCon.Open();:Imports System.Data.AseClientDim oCon As AseConnection = New AseConnection()oCon.ConnectionString="my connection string"oCon.Open()Read more! Adaptive Server Enterprise Data Provider Documentation >>InformixODBCInformix 3.30:"Dsn='';Driver={INFORMIX 3.30 32 BIT};Host=hostname;Server=myserver;Service=service-name;Protocol=olsoctcp;Database=mydb;UID=username;PWD= myPwdInformix-CLI 2.5:"Driver={Informix-CLI 2.5 (32Bit)};Server=myserver;Database=mydb;Uid=username;Pwd=my Pwd"OLE DBIBM Informix OLE DB Provider:"Provider=Ifxoledbc.2;password=myPw;UserID=myUser;Data Source=dbName@serverName;Persist Security Info=true"IngresODBCDSN-less"Provider=MSDASQL.1;DRIVER=Ingres;SRVR=xxxxx;DB=xxx xx;Persist Security Info=False;uid=xxxx;pwd=xxxxx;SELECTLOOPS=N;Extended Properties="""SERVER=xxxxx;DATABASE=xxxxx;SERVERTYPE=IN GRES""Mimer SQLODBCStandard Security:"Driver={MIMER};Database=mydb;Uid=myuser;Pwd=mypw; "Prompt for username and password:"Driver={MIMER};Database=mydb;"LightbaseStandardStandard:"user=USERLOGIN;password=PASSWORD;UDB=USERBASE; server=SERVERNAME"PostgreSQLCore Labs PostgreSQLDirect (.NET)Standard:"User ID=root; Password=pwd; Host=localhost; Port=5432; Database=testdb;Pooling=true; Min Pool Size=0; Max Pool Size=100; Connection Lifetime=0"Read more at Core Lab and the product page.PostgreSQL driverStandard:"DRIVER={PostgreSQL};SERVER=ipaddress;port=5432;DATA BASE=dbname;UID=username;PWD=password;"Npgsql by pgFoundry (.NET)SSL activated:"Server=127.0.0.1;Port=5432;Userid=myuserid;password=m ypw;Protocol=3;SSL=true;Pooling=true;MinPoolSize=3;MaxPool Size=20;Encoding=UNICODE;Timeout=20;SslMode=Require"Without SSL:"Server=127.0.0.1;Port=5432;Userid=myuserid;password=m ypw;Protocol=3;SSL=false;Pooling=true;MinPoolSize=1;MaxPoo lSize=20;Encoding=UNICODE;Timeout=15;SslMode=Disable"Read more in the Npgsql: User's Manual and on the pgFoundry website.ParadoxODBC5.X:Driver={Microsoft Paradox Driver (*.db )};DriverID=538;Fil=Paradox 5.X;DefaultDir=c:\pathToDb\;Dbq=c:\pathToDb\;CollatingSeque nce=ASCII"7.X:"Provider=MSDASQL.1;Persist Security Info=False;Mode=Read;ExtendedProperties='DSN=Paradox;DBQ=C:\myDb;DefaultDir=C:\myDb; DriverId=538;FIL=Paradox7.X;MaxBufferSize=2048;PageTimeout=600;';InitialCatalog=C:\myDb"OleDbConnection (.NET)Standard"Provider=Microsoft.Jet.OLEDB.4.0;DataSource=c:\myDb;Extended Properties=Paradox 5.x;"。

mysql连接字符串的函数MySQL连接字符串是指用于连接MySQL数据库的字符串，其格式为：mysql://user:password@host:port/database。

在使用MySQL连接字符串时，通常需要使用一些函数来构造和处理它。

下面介绍几个常用的MySQL连接字符串函数：1. mysql_connect()函数：用于连接MySQL数据库。

它的参数包括数据库服务器的地址、用户名、密码和要连接的数据库名。

例如： $link = mysql_connect('localhost', 'root', 'password');2. mysql_select_db()函数：用于选择要连接的数据库。

它的参数是所选数据库的名称。

例如：mysql_select_db('test_db');3. mysql_query()函数：用于执行SQL查询语句。

它的参数是要执行的查询语句。

例如：$result = mysql_query('SELECT * FROM customers');4. mysql_fetch_array()函数：用于从查询结果集中获取数据。

它的参数是一个查询结果集，返回值是一个包含查询结果的数组。

例如：while ($row = mysql_fetch_array($result)) {echo $row['name'] . ' - ' . $row['email'];}5. mysql_close()函数：用于关闭数据库连接。

它不需要参数。

例如：mysql_close();以上就是一些常用的MySQL连接字符串函数。

使用它们可以方便地构造和处理MySQL连接字符串，从而实现与MySQL数据库的连接和操作。

sqlite连接字符串的方法摘要：1.SQLite连接概述2.编写SQLite连接字符串的方法3.示例：使用Python和SQLite连接4.连接字符串的参数详解5.总结与建议正文：**一、SQLite连接概述**SQLite是一款轻量级的关系型数据库，它将数据存储在一个磁盘文件中，并提供了一套完整的SQL查询语言。

SQLite具有很多优点，如高性能、易于使用、跨平台等。

在实际项目中，我们可以通过编写连接字符串来连接SQLite 数据库。

**二、编写SQLite连接字符串的方法**要编写SQLite连接字符串，我们需要提供以下几个关键信息：1.数据库文件路径：可以是相对路径或绝对路径，例如：`file:///test.db`。

2.数据库加密方式：可选，默认不加密。

可以使用`sqlite3.加密`进行加密。

3.数据库版本：可选，默认为3.4.数据库别名：可选，用于区分相同路径下的不同数据库。

连接字符串的基本格式如下：```sqlite:///[数据库文件路径][?数据库加密方式][&数据库版本][@数据库别名]```**三、示例：使用Python和SQLite连接**以下是一个使用Python连接SQLite数据库的示例：```pythonimport sqlite3# 编写连接字符串conn_str ="sqlite:///test.db?password=mypassword&timeout=5000"# 连接数据库conn = sqlite3.connect(conn_str)# 操作数据库cursor = conn.cursor()cursor.execute("CREATE TABLE IF NOT EXISTS example (id INTEGER PRIMARY KEY, name TEXT)")cursor.execute("INSERT INTO example (name) VALUES ("John")") mit()# 查询数据cursor.execute("SELECT * FROM example")rows = cursor.fetchall()for row in rows:print(row)# 关闭连接conn.close()```**四、连接字符串参数详解**1.数据库文件路径：必需参数，表示数据库文件的路径。

JDBC数据库连接字符串及连接方法1、连接mysql第一步：从mysql-connector-java目录下面将mysql-connector的jar包导入到lomboz_eclipse中第二步：Class.forName("com.mysql.jdbc.Driver");Connection conn=DriverManager.getConnection("jdbc:mysql://localhost/mydata?"+"user=root&password=root"); 注：“？”前的“mydata”是具体的数据库名称，根据需要连接的具体数据库名称填入。

2、Oracle8/8i/9i数据库（thin模式）第一步：将Oracle提供的jar包导入到编程环境中（如lomboz_eclipse）。

第二步：Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();Connection conn= DriverManager.getConnection(url, user, password);url="jdbc:oracle:thin:@localhost:1521:orcl"; //orcl为数据库的SIDuser="test";password="test";3、连接SQLServer2005Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=mydata","sa","root"); stmt = conn.createStatement();rs = stmt.executeQuery("select * from users");while(rs.next()) {System.out.println(rs.getString(2));}4、连接access首先建立数据库和数据源lxhdb，当数据库没密码时：Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");conn = DriverManager.getConnection("jdbc:odbc:lxhdb");如果有密码conn = DriverManager.getConnection("jdbc:odbc:数据源","用户名","密码");stmt = conn.createStatement();rs = stmt.executeQuery("select * from user");5、SQL Server7.0/2000数据库Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=mydb";//mydb为数据库String user="sa";String password="";Connection conn= DriverManager.getConnection(url,user,password);6、DB2数据库Class.forName("com.ibm.db2.jdbc.app.DB2Driver ").newInstance();String url="jdbc:db2://localhost:5000/sample"; //sample为你的数据库名String user="admin";String password="";Connection conn= DriverManager.getConnection(url,user,password);7、Sybase数据库Class.forName("com.sybase.jdbc.SybDriver").newInstance();String url =" jdbc:sybase:Tds:localhost:5007/myDB";//myDB为你的数据库名Properties sysProps = System.getProperties();SysProps.put("user","userid");SysProps.put("password","user_password");Connection conn= DriverManager.getConnection(url, SysProps);8、Informix数据库Class.forName("rmix.jdbc.IfxDriver").newInstance();String url = "jdbc:informix-sqli://123.45.67.89:1533/myDB:INFORMIXSERVER=myserver; user=testuser;password=testpassword"; //myDB为数据库名Connection conn= DriverManager.getConnection(url);9、PostgreSQL数据库Class.forName("org.postgresql.Driver").newInstance();String url ="jdbc:postgresql://localhost/myDB" //myDB为数据库名String user="myuser";String password="mypassword";Connection conn= DriverManager.getConnection(url,user,password);10、连接excel数据源(ODBC)点击添加，在弹出窗口中选择“Driver do Microsoft Excel(*.xls)”名为myxls Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");conn = DriverManager.getConnection("jdbc:odbc:myxls");stmt = conn.createStatement();rs = stmt.executeQuery("select * from [Sheet1$]");。

数据库连接字符串配置的注意事项数据库连接字符串是在应用程序中配置和使用的重要参数，它决定了应用程序与数据库的连接方式和参数。

正确的连接字符串配置是保证数据库连接稳定和安全的关键因素之一。

本文将介绍一些配置数据库连接字符串时需要注意的事项。

1. 遵循安全原则数据库连接字符串中包含了敏感信息，如用户名、密码等。

为了保护这些信息，务必采取一些安全措施：- 不要将完整的连接字符串存储在源代码中。

可以将其存储在配置文件或环境变量中，并对其进行加密处理。

- 定期更改数据库连接密码，并及时更新相关的连接字符串。

- 限制连接字符串的访问权限，并进行有效的访问控制，确保只有授权的人员能够访问。

2. 指定正确的数据库提供程序数据库提供程序（provider）是用于与数据库交互的驱动程序。

在连接字符串中，必须明确指定所使用的数据库提供程序的名称。

常见的数据库提供程序有：- SQL Server提供程序：System.Data.SqlClient- MySQL提供程序：MySql.Data.MySqlClient- Oracle提供程序：Oracle.ManagedDataAccess.Client- PostgreSQL提供程序：Npgsql- SQLite提供程序：System.Data.SQLite确保正确指定了所用的数据库提供程序，以确保正确的连接和操作。

3. 设置连接安全性选项数据库连接字符串中的连接安全性选项决定了与数据库的安全通信方式。

根据实际情况选择合适的选项：- Integrated Security（集成安全性）：将当前登录 Windows 身份验证的安全上下文用于数据库连接，无需指定额外的用户名和密码。

- User ID（用户身份）和 Password（密码）：明确指定用户名和密码来进行身份验证。

根据具体情况选择适当的连接安全性选项，并确保用户名和密码的安全性。

4. 指定正确的服务器和端口在连接字符串中指定正确的服务器和端口是建立与数据库的连接的基本要求。