access invalid use of null

From: http://goaler.xicp.net/ShowLog.asp? Id = 499We are already familiar with using ASP to call SQL Server Stored Procedures to perform database operations. But do you know that in table-level database access, we can also create and use stored procedures "? Access + ASP is an excellent combination of lightweight Web applications: simple, fast, and compatible, bu

introduce the application of Yii DAO in different scenarios.1. establish a database connection To establish a database connection, create a CDbConnection instance and activate it. To connect to the database, a data source name (DSN) is required to specify the connection information. The user name and password may also be used. When an error occurs during Database Connection (for example, the incorrect DSN or invalid username/password), an exception i

= Socketfactory.createsocket (); SocketAddress localaddr = new inetsocketaddress (localaddress,localport); SocketAddress remoteaddr = new Inetsocketaddress (host, port); Socket.bind (LOCALADDR); Socket.connect (REMOTEADDR, timeout); return socket;}}}2.2 Use the above class to make a new protocol object. (Sslport is specified according to server-side settings, typically 443.)Protocol Protocol = null; Sslign

related to the current state of the application. When the program exits, the information is retained because it has been written to the initialization file. When the program runs again, you can read the data in the initialization file to learn the information about the application during the last running. The following sectionCodeThat is, the number of running times and the last running date of the program are recorded through access to the private i

. common; import com. web. platform. exception. routerException;/*** Service parent class, abstract */public abstract class RouteService {/***/public RouteService () {}/ *** routeTo method, is the starting point of the transaction. * @ Param env * @ throws RouterException */public abstract void routeto (Env env) throws RouterException;/*** routeBack, transaction end point, * @ param env * @ throws RouterException */public abstract void routeback (Env env) throws RouterException;/*** the routeacc

Use Spring Boot to configure dynamic data sources to access multiple databases. I wrote a blog titled Spring + Mybatis + Mysql to build a distributed database access framework. It describes how to configure dynamic data sources through Spring + Mybatis to access multiple databases. However, the previous solution has so

C # several questions about multi-threaded access to the winform control 2010-10-28 from: blog garden font size: [large, small] Abstract:In most cases, you may encounter the problem of using multi-threaded control interface control information. However, we cannot solve this problem using traditional methods. I will introduce it in detail below. When we use winform applications, we usually e

Today, we found a particularly strange problem during the development process: the like query in access is executed in the Access database and the query results can be found, which is executed in the database, select * fromKPProjwhereKpNamelike * test *, but the same statement is null in the c # program. What is the situation? This question Today, we found a par

Use ContentProvider to access non-database dataGenerally, ContentProvider is used to access database data, but sometimes non-database data, such as XML or local data, needs to be specially processed.The most important thing is to customize the Cursor, because the ContentProvider's query method can only return the Cursor reference. Let's talk about the code.

Previously checked on the internet, it seems that you can also read access system tables to obtain, but really want to think about what is, and today on the Internet to find a more convenient way, and, more importantly, this method can also be common to all OLE DB data sources. Here are two ways to use OleDbConnection: GetSchema GetOleDbSchemaTable Look at MSDN Help, write is not clear, or

: Database Name Port_number: Port Number (the default Mysql setting is not changed, and 0 indicates the default value) Unix_socket_name: NULL indicates the default value. Flags: it is used to perform OR operations on some defined bit modes to change some features of the Protocol. Void mysql_close (MYSQL * connection ); Close the connection. If the connection is established by mysql_init, the MySQL structure will be released. The pointer will be

/downloads/prozilla/tarballs/prozilla-2.0.4.tar.bz2 Iii. Appendix: Automatically log on to ftp and download the shell script of the file 1. vi autoftp1.sh #! /Bin/bash Ftp-iun 192.168.20.20 2121 2>/dev/null/tmp/ftp.txt Ftp-iun Rm-rf/tmp/ftp.txt The above method is to use the proxy server to access the Internet on the Linux command line interface. I hope it will

Web applications can be performed by all users, and other operations should be performed by users with special permissions, the connection pool can be defined for the two types of operations respectively, the two connection pools use the same jdbc url, but use different accounts and passwords.The construction function of DBConnectionPool requires all the above data as its parameter. As shown in rows 222 to

Code uses "late binding" (COM objects are created in the memory during running), so you do not need to add COM references to the project, you do not need to install the MS Access Application on the PC. only one Jet engine is required (the Jet engine is included in the MDAC installation package. In Versions later than Windows NT4, the system has already provided this engine ). C # background of Database ACCESS