Mysql.Data 各类版本

Connector/Net 5.2 Release Notes ------------------------------------ Welcome to the release notes for Connector/Net 5.2 There are a number of new features in this release and most of those new features do not come with any change in existing behavior. However there are a couple of changes that users should be aware of. These changes will be documented in the final GA documentation. Please see the changelog for a complete list of new features or bug fixes found in this release. Use Old Syntax is now obsolete ============================== We've had significant feedback from users that they want to use @ to mark their parameters instead of using the ? character. very early versions of the provider did use the @ character but we changed that to ? when we realized that MySQL user variables start with @. Take the following SQL as an example: SET @myusevar=4; SELECT * FROM mytable WHERE id=@id AND var=@myusevar; In this SQL @myusevar is a MySQL controlled user variable and @id is intended to be a user-supplied parameter. The problem is that the provider cannot tell the difference. As we wanted to throw exceptions when parameters are missing upon query execution, we decided to use a different parameter marker character and use the Old Syntax configuration option for applications that were already using @. Since then we've come to realize that users don't use MySQL user variables very often and not using @ makes porting applications from SQL Server to MySQL harder than it needs to be. Therefore, we have decided to move back to suggesting users use the @ character to mark your parameters and we have marked the Use Old Syntax configuration option as obsolete. If you use that option in your connection string, it will have zero effect and a warning message will be logged. Since we realize that many applications are using ?, we intend to support both characters for the foreseeable future. There are side effects that users should be aware of. Here is a bullet list of those effects. - Attempting to add a parameter with the same base name as an existing parameter will throw a duplicate parameter exception. (i.e. Adding ?id when @id is already in the collection) - MySqlParameterCollection.IndexOf will return -1 unless the name matches exactly. (i.e. calling IndexOf("@id") will return -1 even if ?id is in the collection) - Mixing and matching parameters works though it is not recommended. You can define your SQL using @ (SELECT * FROM mytable WHERE id=@id) but then use ? in your paramters. - There is a new connection string option named 'Allow User Variables'. The default value is false. With the default value, the provider doesn't expect to see any user variables in the SQL therefore if it sees @<name> in the SQL it will assume there should be a parameter with the same base name and throw an exception if one is not there. If you intend to use user variables, you have two options. First, continue to use ? for your parameters (not recommended) or set Allow User Variables to true. With this set to true, the provider will not throw an exception if a parameter appears to be missing. TinyInt conversion to Bool is now configurable ============================================== This change was added to 5.1.5 and pulled forward into this release. By default, columns of type TINYINT(1) are still converted to boolean however that can be disabled with a new connection string option. Setting 'Treat Tiny As Boolean' to false will return those columns as integer instead of boolean. Using the new provider schema ============================= This release includes a completely revamped set of web providers along with a completely rewritten provider schema. We will either deliver the SQL scripts in the RTM release or we will deliver a tool that will allow you to upgrade existing servers to the new schema. For this release. the only way to upgrade a given server to the new schema is to add a configuration option for one of your providers. The option is 'autogenerateschema'. By setting this to true, the provider will silently upgrade the server to the new schema. Please note that there is no reversing of this procedure so please just do this on test setups and not on your production systems. Procedure Parameter schema view has changed =========================================== With this release we are now supporting using the procedure parameters information schema view that is available when running against a 6.0 server or later. The benefits of this is that you no longer need elevated privileges to pull this collection. Our provider will use the old code when running against a 5.x server so we modified this code to return a collection that matches the 6.0 collection. This means that we dropped columns such as IS_RESULT (just check for ordinal position = 0) and ROUTINE_TYPE. We hope you enjoy this release and encourage you to test this release with your applications and let us know any problems you find.