ADO参考 摘要:在OLE DB(建立于低层ODBC 之上,是一个针对 SQL 数据源和非SQL 数据源,如邮件和目录等进行操作的应 用程序接口)的基础上,Microsoft 推出了另一个数据访问对象模型:ADO(ActiveX Da ta Object:ActiveX数据对 象)。ADO 采用基于 DAO 和 RDO
ADO参考
摘要:在OLE DB(建立于低层ODBC 之上,是一个针对 SQL 数据源和非SQL 数据源,如邮件和目录等进行操作的应用程序接口)的基础上,Microsoft
推出了另一个数据访问对象模型:ADO(ActiveX Da
ADO对象
ADO 模型中定义了六个常用的对象:Connection、Command、Recordset、Error、Field和Parameter对象,通过这些对象的属性和方法,我们可以很方便地建立数据库连接,执行SQL查询以及存取操作。下图直观地描述了对象之间的关系:
Connection对象
代表打开的、与数据源的连接。一般使用 Connection 对象的集合、方法、和属性执行下列操作:
1、在打开连接前使用 ConnectionString、ConnectionTimeout 和 Mode 属性对连接进行配置。
2、使用 DefaultDatabase 属性设置连接的默认数据库。
3、使用 Provider 属性指定 OLE DB 提供者。
4、使用 Open 方法建立到数据源的物理连接。使用 Close 方法将其断开。
5、使用 Execute 方法执行对连接的命令,并使用 CommandTimeout 属性对执行进行配置。
6、使用 BeginTrans、CommitTrans 和 RollbackTrans 方法以及 Attributes 属性管理打开的连接上的事务(如果提供者支持则包括嵌套的事务)。
7、使用 Errors 集合检查数据源返回的错误。
Command对象
定义了对数据源执行的命令,我们可以使用 Command 对象的集合、方法、属性进行下列操作:
1、使用 CommandText 属性定义命令(例如,SQL 语句)的可执行文本。
2、通过 Parameter 对象和 Parameters 集合定义参数化查询或存储过程参数。
3、使用 Execute 方法执行命令并在适当的时候返回 Recordset 对象。
4、执行前使用 CommandType 属性指定命令类型以优化性能。
5、使用 CommandTimeout 属性设置等待命令执行的秒数。
6、通过设置 ActiveConnection 属性关联打开的连接。
7、设置 Name 属性将 Command 标识为与 Connection 对象关联的方法。
8、将 Command 对象传送给 Recordset 的 Source 属性以便获取数据。
ADO连接EXCEL2003表
Conn.Open "provider=microsoft.jet.oledb.4.0;extended properties=excel 8.0;data source=" & 文件全路 Cnn.Open "provider=microsoft.jet.oledb.4.0;Extended properties='excel 8.0;hdr=no';data source=" & 路径设置
“HDR=NO"应该表示所选区域首行不做为标题,如果不设置该项,系统默认将首行非空记录做为ADO记录集的标题行
ADO连接txt文件
ActiveSheet.Cells.Clear myText = "学生成绩.txt" myPath = ThisWorkbook.Path CnnStr = "Driver={Microsoft Text Driver (*.txt; *.csv)};" & "DBQ=" & myPath ' Cnn.Open CnnStr rs.Open myText, cnn, adopenkeset, adLockOptimistic ADO连接ACCESS2003的数据库 strAccess = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + _ThisWorkbook.Path + "\data\数据库档案.MDB" + _";Jet OLEDB:Database Password=" & "123" '定义连接字符串 数据源 密码(最长20个字符) Set ADOcn = New ADODB.Connection ' 赋值变量为对象引用 ADOcn.Open strAccess '打开连接
ADO连接FOXPRO 6.0的数据库
set conn =createobject("adodb.connection") set rs=createobject("adodb.recordset") sql="select * from aa.dbf" conn.open "driver={microsoft visual foxpro driver };sourcetype=dbf;excelusive=no;sourcedb=" & 文件路径 rs.open sql ,conn msgbox rs.recordcount rs.close conn.close conn=nothing rs=nothing需要安装foxpro 的odbc驱动
ADO连接SQL SERVER的数据库
Dim cnn1 As ADODB.Connection Dim strCnn As String ' 打开连接。 strCnn = "Provider=sqloledb;" & _ "Data Source=srv;Initial Catalog=pubs;User Id=sa;Password=; " cnn1.Open strCnn ADO连接ACCESS2007的数据库 con.Open "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & Access2007数据源 & _ ";Jet OLEDB:Database Password=" & 密码 con.Open "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & Excel2007数据源 & _ ";Jet OLEDB:Database Password=" & 密码
ADO连接oracle数据库
Sub connect_数据库() Dim strconnt As String Set connt = New ADODB.Connection Dim rs As Object Set rs = New ADODB.Recordset Dim sevip, Db, user, pwd As String '设服务器地址、所连数据,及登录用户密码 sevip = "****" Db = "****" user = "****" pwd = "****" strconnt = "DRIVER={Microsoft ODBC for Oracle};Password=apps;User ID=apps;Data Source=demo" ' connt.ConnectionString = strconnt connt.Open End Sub
ADO连接mysql数据库
Sub connect_数据库() Dim strconnt As String strconnt = "" Set connt = New ADODB.Connection Dim rs As Object Set rs = New ADODB.Recordset Dim sevip, Db, user, pwd As String '设服务器地址、所连数据,及登录用户密码 sevip = "192.168.*.*" Db = "***" user = "***" pwd = "****" strconnt = "DRIVER={MySql ODBC 3.51 Driver};SERVER=" & sevip & ";Database=" & Db & ";Uid=" & user & ";Pwd=" & pwd & ";Stmt=set names GBK" ' connt.ConnectionString = strconnt connt.Open End Sub

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ChooseCHARforfixed-lengthdata,VARCHARforvariable-lengthdata,andTEXTforlargetextfields.1)CHARisefficientforconsistent-lengthdatalikecodes.2)VARCHARsuitsvariable-lengthdatalikenames,balancingflexibilityandperformance.3)TEXTisidealforlargetextslikeartic

Best practices for handling string data types and indexes in MySQL include: 1) Selecting the appropriate string type, such as CHAR for fixed length, VARCHAR for variable length, and TEXT for large text; 2) Be cautious in indexing, avoid over-indexing, and create indexes for common queries; 3) Use prefix indexes and full-text indexes to optimize long string searches; 4) Regularly monitor and optimize indexes to keep indexes small and efficient. Through these methods, we can balance read and write performance and improve database efficiency.


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