When defining an entity with a DatabaseGeneratedOption.Identity value with Entity Framework Code First, you can now leave this column out of the column list for an INSERT or UPDATE statement. This feature is especially useful for defining a column with a default value corresponding to the CURRENT_TIMESTAMP() return value:

[DatabaseGenerated(DatabaseGeneratedOption.Identity)] 
public DateTime DateCreated { get; set; } 

(Bug #15935094)

Connector/Net now supports the MySQL 5.6 feature to store connection-specific data in the server. A Connector/Net application can supply to the server a list of key/value pairs at login time. When you specify the connection option Connect_Attrs, a predefined set of attribute values is sent to the server. Connector/Net automatically transmits the following attributes:

To examine these connection-specific attributes on the server, query the Performance Schema tables described in Performance Schema Connection Attribute Tables. (Bug #15935112)

Connector/Net now supports the MySQL 5.6 password expiration protocol. See ALTER USER for the syntax to expire the password for a user. When you open a connection through Connection/Net that logs in as a user with an expired password, any statement issued through the connection produces a SET PASSWORD exception. When you create a connection in Visual Studio Server Explorer to a user with an expired password, a dialog prompts for a new password, after which the connection succeeds. (Bug #15935104)

Connector/Net now supports SHA-256 hashing for user account passwords. After you create an account following the steps outlined in The SHA-256 Authentication Plugin, just open a Connector/Net connection passing user and password. This feature works in both SSL and non-SSL secured connections. (Bug #15935128)

Setting cascadeDelete to true in DbMigration.AddForeignKey() results in ON DELETE RESTRICT foreign key constraints in generated DDL, rather than ON DELETE CASCADE as expected. (Bug #16398432, Bug #68457)

When running a multithreaded service, you might receive the exception:

The given key was not present in the dictionary

The issue was fixed by enhancing the locking code within the ConnectionStringBuilder class. (Bug #16310698, Bug #68217)

When using EntityFramework 4.3 and Code First, generated foreign key identifiers could be longer than 64 characters, causing MySQLException errors. The fix renames any too-long identifiers using the name format FK_guid, where guid is a global unique identifier generated at runtime. (Bug #16286397, Bug #67285)

Connector/Net would throw a MySqlException exception when an invalid collection was passed to the GetSchema method. Now it throws an ArgumentException when an invalid collection name is passed to GetSchema, to be compliant with the API spec of System.Data.Common.DbConnection.GetSchema. The new behavior provides better compatibility with other data access providers such as ADO.Net. (Bug #16271425, Bug #67901)

When debugging a stored routine containing a DECIMAL variable, you might encounter the error:

mismatched input ')' expecting COMMA

A workaround was to include a second parameter of 0 in the variable declaration:

DECLARE var_name DECIMAL(3, 0)

The fix allows the Connector/Net debugger to handle DECIMAL variable declarations without the optional second field. (Bug #16079735, Bug #67975)

If a DateTime type in MySQL 5.6 was defined with milliseconds precision using Entity Framework Code First or EF Model First, the expected DateTime(n) column did not include the precision specification. (Bug #15972773)

Specifying the Default Command Timeout option in a connection string used with the MySQL Entity Framework provider had no effect. The command timeout was always 30 seconds. (Bug #14825670, Bug #67171)

A System.InvalidCastException exception could occur when calling a stored function. A workaround was to specify the CheckParameters=false connection option. (Bug #13864627, Bug #64633)

The medium trust support using the MySQLClientPermissions class is now more flexible: in addition to the original deployment method, where the library is installed in the Global Assembly Cache (GAC), you can also install the library within a bin or lib folder inside the project or solution. When the library is deployed somewhere other than the GAC, the only protocol supported is TCP/IP. Existing applications that use the library installed in the GAC must now include an extra connection option, includesecurityasserts=true. For details, see Working with Partial Trust / Medium Trust. (Bug #14668820, Bug #65036)

Performance: The LINQ to SQL data provider for MySQL was generating inefficient code for the StartsWith() and Contains() methods, calling the MySQL LOCATE() function rather than using a LIKE operator with a % wildcard. The fix causes both methods to use the LIKE syntax, although only StartsWith() gains a substantial performance improvement. Queries involving the StartsWith() method can now take advantage of an index on the corresponding column. (Bug #14009363, Bug #64935)

Performance: The LINQ to SQL data provider for MySQL was generating inefficient code for the Contains() method, producing a query with multiple OR clauses instead of the more efficient IN clause. (Bug #14016344, Bug #64934)

When using Entity Frameworks: Code First in Visual Studio 2012 and using a GUID as the primary key in a class, the following error could occur:

Incorrect column specifier for column 'column_name'.

Connector/Net was applying the AUTO_INCREMENT attribute to the column, which requires that the column use an integer data type. (Bug #15834176, Bug #67450)

Calling the method FirstOrDefault “LINQ to Entities” queries caused a System.Data.EntityCommandCompilationException exception. (Bug #15856964, Bug #67377)

Connection attempts using IPV6 addresses in Connector/Net would fail. (Bug #14835718, Bug #67253)

Visual Studio 2012 projects could sometimes give the following error dialog:

Failed to merge object(s). 

Keyword not supported. 
Parameter name: AttachDbFilename. 

This issue affected mostly VisualStudio 2012 projects, either migrated from VisualStudio 2010 or including web sites created with VS2010, connecting to a MySQL 5.5 server. (Bug #14733472, Bug #66880)

When an application starts up, creates a connection, and then goes idle after a single database operation, the connections are now cleaned up more quickly: typically after an idle time of 3 minutes rather than 6 minutes. This optimization is especially useful for ASP.net applications on low-traffic sites. (Bug #14652624, Bug #66472)

Under some circumstances, setting CacheServerProperties=true in the connection string could cause a Packet too large error. With connection pooling enabled and CacheServerProperties=true, the first connection worked as expected, but the second, third, and so on connections would fail if the query exceeded 1024 bytes. (Bug #14593547, Bug #66578)

Connector/Net did not support creating an entity with a key of type string. During database creation, a MySqlException was thrown saying BLOB/TEXT column 'Name' used in key specification without a key length. The DDL produced by the provider specified a MEDIUMTEXT column for the primary key without specifying a length for the key. This fix is particularly important when working with Entity Framework versions 4.3 and later, since the __MigrationsHitory table (which replaces the EdmMetadata table) uses a string property as its key. (Bug #14540202, Bug #65289, Bug #64288)

The ExecuteNonQuery() could return an error Parameter '?' must be defined, when attempting to execute a statement such as:

insert into table_name (Field1, Field1) VALUES(?,?)

That is, when referencing the same field twice with two different ? placeholders. (Bug #14499549, Bug #66060)

Customizing precision by calling the HasPrecision() method within the OnModelCreating() method in a Code First project would always produce precision settings (10,2) rather than the specified precision. (Bug #14469048, Bug #65001)

The MySQL Connector/Net EntityFramework provider would throw NullReferenceException when trying to insert a new record with an empty VALUES clause. Such an INSERT should work when the only required (NOT NULL) column in the table is a primary key auto-increment column. (Bug #14479715, Bug #66066)

When building commands through the MySql.Data.MySqlClient.MySqlCommand() class, memory could be leaked because some IO.MemoryStream instances were not being freed efficiently. The memory leak could be an issue in SQL-heavy applications, for example a logging application processing large numbers of INSERT statements. (Bug #14468204, Bug #65696)

Using the Entity Data Model Designer decimal type and CreateDatabase function, the values were stored with 0 digits at the right of the decimal point. With this fix, the default is 2 digits to the right of the decimal point, and any precision specified through the Entity Data Model Designer is applied correctly. (Bug #14474342, Bug #65127)

When using a MySQL database set up as UTF32 as an ASP.net membership database, web applications could give a “key too long” error, and the Website Administration Tool would not connect to providers. The cause was that the column my_aspnet_sessions.SessionId, when converted from Latin1 character set to UTF32 with 4 bytes per character, exceeded the length limit for a primary key:

Specified key was too long; max key length is 767 bytes

(Bug #14495292, Bug #65144)

When using the ASP.net web security functionality with a MySQL database, using features that access the my_aspnet_usersinroles table caused an exception:

MySql.Data.MySqlClient.MySqlException: Table 'testdb.my_aspnet_usersinrole' doesn't exist.

For example, this error could occur when trying to remove the user from a role or find users in a role. The fix corrects the spelling of the table name to my_aspnet_usersinroles. (Bug #14405338, Bug #65805)

Although the member variable MySqlCommand.LastInsertedId was a 64-bit long, its value was effectively capped at the maximum value of Int32 (2,147,483,647). If a primary key exceeded this value, the value of LastInsertedId was wrong. This mismatch could be an issue for tables with large numbers of rows. (Bug #14171960, Bug #65452)

When using Entity Framework with Connector/Net, the association property OnDelete was not taken into account in the CreateDatabaseScript function of the ObjectContext, leading to an error message System.Data.UpdateException was unhandled. The SQL generated by the CreateDatabaseScript function was missing ON DELETE and ON UPDATE clauses. These clauses were filled in correctly by the DDL generation wizard. (Bug #14008752, Bug #64779)

A call to a stored procedure or function in an application using the Code First entity framework could result in an error:

Unhandled Exception: MySql.Data.MySqlClient.MySqlException: You have an error 
in your SQL syntax; ...

The code change allows syntax such as the following to invoke a stored procedure, without using the CALL statement and without using CommandType.StoredProcedure.

int count = myContext.Database.SqlQuery<int>("GetCount").First(); 

(Bug #14008699, Bug #64999)

When using the Entity Framework Code First approach, the generated code could be incorrect:

(Bug #13900091, Bug #64216)

The milliseconds portion of a date/time value was not stored correctly for the datatype DATETIME(3). (Bug #13881444, Bug #64686)

When the length of a VARCHAR column was edited in Table Designer, the data type could be saved incorrectly as BIT. (Bug #13916560)

Any sequence of Take(n) method calls followed by Count or LongCount would cause a System.Data.EntityCommandCompilationException error. (Bug #13913047, Bug #64749)

A timing issue with the GetItemExclusive, SetAndReleaseItemExclusive, and GetItem functions could cause an application to freeze for almost 2 minutes if GetItem was called at a particular moment when a session was already locked as read-only. (Bug #13733054, Bug #63997)

When using the MySqlProfileProvider, calling the function ProfileManager.DeleteProfiles could throw an InvalidCastException exception. (Bug #13790123, Bug #64470)

In Visual Studio Table Designer, the name of a new index was always derived from the name of the table and could not be changed. (Bug #13613801)

When using the Entity Framework Code First approach, the generated code could be use the MEDIUMTEXT data type in contexts where other types such as VARCHAR were more appropriate, leading to errors such as:

error 0064: Facet 'MaxLength' must not be specified for type 'mediumtext'.

(Bug #13582335, Bug #63920)

In Visual Studio 2005, adding a new data connection through the Server Explorer produced an error message: Package Load Failure. The Visual Studio plugin was dynamically linked against VS2008 version of assembly Microsoft.VisualStudio.Data (v9.0). The fixed plugin links with the VS2005 version (v8.0) of that library instead instead, which is upward compatible with later Visual Studio versions. (Bug #13491674, Bug #63073)

In “LINQ to Entity” queries, including a child entity (1-n) and its entities (n-n) returned the wrong results. For example:

db.Authors.Include("Books.Editions").AsEnumerable().First();

(Bug #13491698, Bug #62801)

Formerly, cleanup operations for expired sessions were fully automatic, with no ability to catch the timeout event and do application-specific cleanup. This fix adds a enableSessionExpireCallback connection option to let developers catch the event when a session expires. When enableSessionExpireCallback is enabled, the global.asax.session_end event is raised before data is deleted from the my_aspnet_sessions table. When enableSessionExpireCallback is disabled, the data is deleted from the my_aspnet_sessions table without raising the event first. The timeout period for session expiry is specified in the web.config file, in the timeout option of the sessionState section. (Bug #13354935, Bug #62266)

In Visual Studio Table Designer, if you tried to save a new table using an existing table name, subsequently you would not be prompted to choose a new name, preventing you from saving the table. (Bug #13785918)

When creating a Visual Studio Web Application Project, using the ADO.NET Entity Data Model and generating the model from a database, the Entity Framework Model was not created. This operation gave an error:

Access denied for user 'root'@'localhost' (using password: NO)

(Bug #13610452)

When creating a project in VisualStudio using a .NET framework such as 3.0 or 3.5 (anything less than 4.0), the Connector/Net library (MySql.Data.dll) was not listed in the Add References dialog box. The workaround was to browse to the library and add it manually. (Bug #13491678, Bug #60462)

The performance when setting the CommandText property on the MySqlCommand class was improved by enhancing the efficiency of a string comparison operation. (Bug #13739383, Bug #64012)

Fixed MySqlTime parsing to avoid throwing an exception when handling milliseconds (as result of a timediff operation). (Bug #13708884, Bug #64268)

In Visual Studio Table Designer, when adding a second foreign key, the new name was incorrectly assigned to the first foreign key in the list. (Bug #13613824)

In Visual Studio Table Designer, changes to a field were sometimes not detected until you switched focus away from that field. (Bug #13613755)

In Visual Studio Table Designer, when editing a foreign key relationship, choosing a column name on the left side made that column name unavailable on the right side. (Bug #13615258)

In Visual Studio Table Designer, an error could occur if you added and deleted column information for foreign keys in a particular sequence. (Bug #13610235)

In Visual Studio Table Designer, deleting a foreign key relationship in the Relationship dialog required clicking twice. (Bug #13610283)

In Visual Studio Table Designer, modifying the Columns field in the Indexes/Keys dialog multiple times could cause an error. (Bug #13613765)

In Visual Studio Table Designer, it was possible to save a new foreign key relationship without filling in the fields of the Foreign Key Relationship dialog. (Bug #13613839)

In Visual Studio Table Designer, changing the length of a VARCHAR field could cause an error. (Bug #13611677)

If MySqlCommand.CommandText was equal to null, then MySqlCommand.ExecuteReader() would throw the wrong exception: NullReferenceException instead of InvalidOperationException. (Bug #13624659, Bug #64092)

When using connection pooling, the connections in the pool were not automatically closed upon application exit. With the setting log-warnings=2, you could encounter Aborted connection errors in the MySQL error log. The workaround was to explicitly call MySql.Data.MySqlClient.MySqlConnection.ClearAllPools(); upon exiting the application. (Bug #13629471, Bug #63942)

The MySQL script generated by using the function CreateDatabaseScript used names with incorrect singular/plural forms. (Bug #13582837, Bug #62150)

In Visual Studio Table Designer, the Add -> Function Import... dialog could close prematurely when you pressed the Get Column Information button. (Bug #13511736)

When designating a primary key for a table in Table Designer, the key icon could fail to appear until the Table Designer was restarted. (Bug #13481246)

In Table Designer for Visual Studio, trying to delete foreign keys from an InnoDB table showed an error, and the change was not saved. (Bug #13481362)

After an UPDATE statement, Connector/Net would generate incorrect SELECT SQL statements if a value in the WHERE clause was not also present in the SET clause of the UPDATE. (Bug #13491689, Bug #62134)

IntelliSense would emit an error when the "-" (minus) character was typed. (Bug #13522344)

Added better IntelliSense support, including auto-completion when editing stored procedures or .mysql files. For more information, see Using IntelliSense in the SQL Editor.

Adds a MySqlClientPermission class to help users define the security policies for the database connections within any application using a MySQL database.

Added better partial-trust support, thus allowing Connector/NET to run in a partial trust scenario. It will work correctly in a medium-trust level environment when the library is installed in the GAC. For more information, see Working with Partial Trust / Medium Trust.

Added fractional seconds support, as per MySQL Server 5.6 and above. For more information, see Fractional Seconds in Time Values

Added “interceptor” classes for exceptions and commands. For more information, see Using the Connector/Net Interceptor Classes.

The MySqlDataReader.GetDateTime() method was not recognizing that TIMESTAMP values had already been converted to the local time zone of the MySQL server, which could cause incorrect results if the value was later processed through the ToLocalTime() method. The fix causes the Kind property to be correctly set to Local rather than Unspecified. (Bug #13591554, Bug #63812)

Visual Studio 2010 Table Designer could give an error “Object reference not set to an instance of an object” for schemas with certain combinations of column names and foreign key references. The SQL syntax was incorrect for the ALTER TABLE statement generated by the Table Designer. (Bug #13591545, Bug #63714)