Chapter 7. Data Access Interfaces

The base constructor initializes all fields to their default values. The following table shows initial property values for an instance of VirtuosoCommand.

You can change the value for any of these properties through a separate call to the property.

Includes the source database name and other parameters needed to establish the initial connection. The default value is an empty string.

ConnectionString has the following syntax: Each connection string is a sequence of settings Individual settings are separated by semicolons. Each setting is a pair of name and value delimited by the equal sign. Whitespace is ignored on either side of both names and values. Names are case insensitive. The value part can be quoted by either single or double quote characters or remain unquoted at all. However if it includes a semicolon, single quote, or double quote characters, it must be enclosed in either type of quotes. To embed the same character that is used for enclosing the value the character within the value must be doubled.

The following table lists the valid names for values within the ConnectionString:

IDbCommand.ConnectionString

The ConnectionString is similar to an OLE DB connection string, but is not identical. Unlike OLE DB or ADO, the connection string that is returned is the same as the user set ConnectionString minus security information if the Persist Security Info value is set to false (default). The Virtuoso ADO.NET Data Provider neither persists nor returns the password in a connection string unless you set Persist Security Info to true.

The ConnectionString property can be set only when the connection is closed. Many of the connection string values have corresponding read-only properties. When the connection string is set, all of these properties are updated, except when an error is detected; in this case, none of the properties are updated. VirtuosoConnection properties return only those settings contained in the ConnectionString .

Resetting the ConnectionString on a closed connection resets all connection string values (and related properties) including the password. For example, if you set a connection string that includes "Database=Demo ", and then reset the connection string to "Data Source=myserver;User ID=dba;Password=dba ", the Database property is no longer set to Demo .

The connection string is parsed immediately after being set. If errors in syntax are found when parsing, a runtime exception (e.g., ArgumentException ) is generated. Other errors can be found only when an attempt is made to open the connection.

The SQL statement or stored procedure to execute. The default value is an empty string ("").

IDbCommand.CommandText

When the CommandType property is set to StoredProcedure, the CommandText property should be set using standard ODBC stored procedure escape sequences. Setting the CommandText to the name of the stored procedure does not function as it does for some other .NET data providers.

The Virtuoso .NET Data Provider does not support named parameters for passing parameters to a SQL statement or a stored procedure called by an OleDbCommand when CommandType is set to Text. In this case, the question mark (?) placeholder must be used. For example:

SELECT * FROM Customers WHERE CustomerID = ?

As a result, the order in which VirtuosoParameter objects are added to the VirtuosoParameterCollection must directly correspond to the position of the question mark placeholder for the parameter.

The time (in seconds) to wait for the command to execute. The default is 30 seconds.

IDbCommand.CommandTimeout

A value of zero (0) specifies no limit to the wait time, rather than no wait time, and therefore should be avoided.

One of the System.Data.CommandType values. The default is Text.

IDbCommand.CommandType

When the CommandType property is set to StoredProcedure, you should set the CommandText property to the full ODBC call syntax. The command then executes this stored procedure when you call one of the Execute methods (for example, ExecuteReader or ExecuteNonQuery).

The Connection, CommandType and CommandText properties cannot be set if the current connection is performing an execute or fetch operation.

The Virtuoso .NET Data Provider does not support passing named parameters to an SQL statement or to a stored procedure called by a VirtuosoCommand. In either of these cases, use the question mark (?) placeholder. For example:

SELECT * FROM Customers WHERE CustomerID = ?

The order in which VirtuosoParameter objects are added to the VirtuosoParameterCollection must directly correspond to the position of the question mark placeholder for the parameter.

The connection to a Virtuoso database. The default is a null value.

The parameters of the SQL statement or stored procedure. The default is an empty collection.

When CommandType is set to Text, the Virtuoso .NET Data Provider does not support passing named parameters to an SQL statement or to a stored procedure called by an VirtuosoCommand. In either of these cases, use the question mark (?) placeholder. For example:

SELECT * FROM Customers WHERE CustomerID = ?

The order in which VirtuosoParameter objects are added to the VirtuosoParameterCollection must directly correspond to the position of the question mark placeholder for the parameter in the command text.

	Note:
	If the parameters in the collection do not match the requirements of the query to be executed, an error may result.

A VirtuosoTransaction. The default is a null value.

You cannot set the Transaction property if it is already set to a specific value, and the command is in the process of executing. If you set the transaction property to an VirtuosoTransaction object that is not connected to the same VirtuosoConnection as the VirtuosoCommand object, an exception will be thrown the next time you attempt to execute a statement.

One of the System.Data.UpdateRowSource values.

IDbCommand.UpdatedRowSource

A VirtuosoParameter object.

The CreateParameter method is a strongly-typed version of IDbCommand.CreateParameter.

For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command. For all other types of statements, the return value is -1.

IDbCommand.ExecuteNonQuery

You can use ExecuteNonQuery to perform catalog operations (for example, querying the structure of a database or creating database objects such as tables); or to change the data in a database, without using a DataSet, by executing UPDATE, INSERT, or DELETE statements.

Although ExecuteNonQuery does not return any rows, any output parameters or return values mapped to parameters are populated with data.

Sends the CommandText to the Connection and builds a VirtuosoDataReader.

Sends the CommandText to the Connection and builds a VirtuosoDataReader using one of the CommandBehavior values.

The first column of the first row in the resultset.

IDbCommand.ExecuteScalar

Use the ExecuteScalar method to retrieve a single value (for example, an aggregate value) from a database. This requires less code than using the ExecuteReader method, and then performing the operations necessary to generate the single value using the data returned by a VirtuosoDataReader.

A typical ExecuteScalar query can be formatted as in the following C# example:

command.CommandText = "select count(*) from foobar";
int count = (int) command.ExecuteScalar();

This member supports the .NET Framework infrastructure and is not intended to be used directly from your code.

This member supports the .NET Framework infrastructure and is not intended to be used directly from your code.

IDbCommand.Prepare

The VirtuosoCommandBuilder registers itself as a listener for RowUpdating events that are generated by the VirtuosoDataAdapter specified in this property.

A VirtuosoDataAdapter object.

The VirtuosoCommandBuilder registers itself as a listener for RowUpdating events that are generated by the VirtuosoDataAdapter specified in this property.

The beginning character or characters to use. The default is an empty string.

Database objects in Virtuoso servers can contain any valid characters, including spaces, commas, and semicolons. To accommodate this capability, use the QuotePrefix and QuoteSuffix properties to specify delimiters such as a left bracket and a right bracket to encapsulate the object name.

The ending character or characters to use. The default is an empty string.

Database objects in Virtuoso servers can contain any valid characters, including spaces, commas, and semicolons. To accommodate this capability, use the QuotePrefix and QuoteSuffix properties to specify delimiters such as a left bracket and a right bracket to encapsulate the object name.

DeriveParameters overwrites any existing parameter information for the VirtuosoCommand. DeriveParameters requires an extra call to the data server to obtain the information. If the parameter information is known in advance, it is more efficient to populate the parameters collection by setting the information explicitly.

For more information, see "Using Stored Procedures with a Command" in the Microsoft® .NET Framework SDK documentation.

This method is called by the public Dispose method and the Finalize method. Dispose() invokes the protected Dispose(Boolean) method with the disposing parameter set to true. Finalize invokes Dispose with disposing set to false.

When the disposing parameter is true, the method releases all resources held by any managed objects that this VirtuosoCommand references. It does this by invoking the Dispose() method of each referenced object.

For more information about Dispose and Finalize, see "Cleaning Up Unmanaged Resources," and "Overriding the Finalize Method," in the .NET Framework SDK documentation.

The automatically generated VirtuosoCommand object required to perform deletions.

You can use the GetDeleteCommand method for informational or troubleshooting purposes because it returns the VirtuosoCommand object to be executed.

You can also use GetDeleteCommand as the basis of a modified command. For example, you might call GetDeleteCommand and modify the CommandTimeout value, and then explicitly set that on the VirtuosoDataAdapter.

After the SQL statement is first generated, you must explicitly call RefreshSchema if you change the statement in any way. Otherwise, the GetDeleteCommand still will be using information from the previous statement, which might not be correct. The SQL statements are first generated when the application calls either Update or GetDeleteCommand.

The automatically generated VirtuosoCommand object required to perform insertions.

You can use the GetInsertCommand method for informational or troubleshooting purposes because it returns the VirtuosoCommand object to be executed.

You can also use GetInsertCommand as the basis of a modified command. For example, you might call GetInsertCommand and modify the CommandTimeout value, and then explicitly set that on the VirtuosoDataAdapter.

After the SQL statement is first generated, you must explicitly call RefreshSchema if you change the statement in any way. Otherwise, the GetInsertCommand still will be using information from the previous statement, which might not be correct. The SQL statements are first generated when the application calls either Update or GetInsertCommand.

The automatically generated VirtuosoCommand object required to perform updates.

You can use the GetUpdateCommand method for informational or troubleshooting purposes because it returns the VirtuosoCommand object to be executed.

You can also use GetUpdateCommand as the basis of a modified command. For example, you might call GetUpdateCommand and modify the CommandTimeout value, and then explicitly set that on the VirtuosoDataAdapter.

After the SQL statement is first generated, you must explicitly call RefreshSchema if you change the statement in any way. Otherwise, the GetUpdateCommand still will be using information from the previous statement, which might not be correct. The SQL statements are first generated when the application calls either Update or GetUpdateCommand.

You should call RefreshSchema whenever the SelectCommand value of the VirtuosoDataAdapter changes.

When a new instance of VirtuosoConnection is created, the read/write properties are set to the following initial values unless they are specifically set using their associated keywords in the ConnectionString property.

You can change the value for these properties only by using the ConnectionString property

When a new instance of VirtuosoConnection is created, the read/write properties are set to the following initial values unless they are specifically set using their associated keywords in the ConnectionString property.

You can change the value for these properties only by using the ConnectionString property

The connection string that includes the source database name, and other parameters needed to establish the initial connection. The default value is an empty string.

IDbConnection.ConnectionString

The ConnectionString is similar to an OLE DB connection string, but is not identical. Unlike OLE DB or ADO, the connection string that is returned is the same as the user-set ConnectionString minus security information if the Persist Security Info value is set to false (default). The Virtuoso .NET Data Provider does not persist or return the password in a connection string unless you set Persist Security Info to true.

The ConnectionString property can be set only when the connection is closed. Many of the connection string values have corresponding read-only properties. When the connection string is set, all of these properties are updated, except when an error is detected. In this case, none of the properties are updated. VirtuosoConnection properties return only those settings contained in the ConnectionString.

Resetting the ConnectionString on a closed connection resets all connection string values (and related properties) including the password. For example, if you set a connection string that includes "Database=Demo", and then reset the connection string to "Data Source=myserver;User ID=dba;Password=dba", the Database property is no longer set to northwind.

The connection string is parsed immediately after being set. If errors in syntax are found when parsing, a runtime exception, such as ArgumentException, is generated. Other errors can be found only when an attempt is made to Open the connection.

Connection string has the following syntax. Each connection string is a sequence of settings Individual settings are separated by semicolons. Each setting is a pair of name and value delimited by the equal sign. Whitespace is ignored on either side of both names and values. Names are case insensitive. The value part can be quoted by either single or double quote characters or remain unquoted at all. However if it includes a semicolon, single quote, or double quote characters, it must be enclosed in either type of quotes. To embed the same character that is used for enclosing the value the character within the value must be doubled.

The following table lists the valid names for values within the ConnectionString.

The time (in seconds) to wait for a connection to open. The default value is 15 seconds.

IDbConnection.ConnectionTimeout

A value of 0 indicates no limit, and should be avoided in a ConnectionString because an attempt to connect will wait indefinitely.

The name of the current database or the name of the database to be used once a connection is open. The default value is an empty string.

IDbConnection.Database

Initially, the Database property is set in the connection string. The Database property can be updated by using the ChangeDatabase method.

A bitwise combination of the ConnectionState values. The default is Closed.

The allowed state changes are:

Begins a database transaction.

Begins a database transaction with the specified isolation level.

IDbConnection.ChangeDatabase

The value parameter must contain a valid database name, and cannot contain a null value, an empty string (""), or a string with only blank characters.

IDbConnection.Close

The Close method rolls back any pending transactions. It then releases the connection to the connection pool, or closes the connection if connection pooling is disabled.

An application can call Close more than one time. No exception is generated.

A VirtuosoCommand object.

You can enlist in an existing distributed transaction using the EnlistDistributedTransaction method if auto-enlistment is disabled. Enlisting in an existing distributed transaction ensures that, if the transaction is committed or rolled back, modifications made by the code at the data source are also committed or rolled back.

This member supports the Microsoft® .NET Framework infrastructure and is not intended to be used directly from your code.

This member supports the Microsoft® .NET Framework infrastructure and is not intended to be used directly from your code.

IDbConnection.Open

The VirtuosoConnection draws an open connection from the connection pool if one is available. Otherwise, it establishes a new connection to an instance of Virtuoso server.

	Note:
	If the VirtuosoConnection goes out of scope, it is not closed. Therefore, you must explicitly close the connection by calling Close or Dispose.

When you create an instance of VirtuosoDataAdapter, the following read/write properties are set to their default values, as shown in the table.

You can change the value of any of these properties through a separate call to the property.

This implementation of the VirtuosoDataAdapter constructor sets the SelectCommand property to the value specified in the selectCommand parameter.

When you create an instance of VirtuosoDataAdapter, the following read/write properties are set to their default values, as shown in the table.

You can change the value of any of these properties through a separate call to the property.

A VirtuosoCommand used during an update operation to delete records in the database that correspond to deleted rows in the DataSet.

When DeleteCommand is assigned to a previously created VirtuosoCommand, the VirtuosoCommand is not cloned. The DeleteCommand maintains a reference to the previously created VirtuosoCommand object.

A VirtuosoCommand used during an update operation to insert records in the database that correspond to new rows in the DataSet.

When InsertCommand is assigned to a previously created VirtuosoCommand, the VirtuosoCommand is not cloned. The InsertCommand maintains a reference to the previously created VirtuosoCommand object.

A VirtuosoCommand used during Fill to select records from the database for placement in the DataSet.

When SelectCommand is assigned to a previously created VirtuosoCommand, the VirtuosoCommand is not cloned. The SelectCommand maintains a reference to the previously created VirtuosoCommand object.

If the SelectCommand does not return any rows, no tables are added to the DataSet, and no exception is raised.

A VirtuosoCommand used during an update operation to update records in the database that correspond to modified rows in the DataSet.

When UpdateCommand is assigned to a previously created VirtuosoCommand, the VirtuosoCommand is not cloned. The UpdateCommand maintains a reference to the previously created VirtuosoCommand object.

Raising an event invokes the event handler through a delegate. For an overview, see "Raising an Event" in the Microsoft® .NET Framework SDK documentation.

Raising an event invokes the event handler through a delegate. For an overview, see "Raising an Event" in the Microsoft® .NET Framework SDK documentation.

The event handler receives an argument of type VirtuosoRowUpdatedEventArgs containing data related to this event. The following VirtuosoRowUpdatedEventArgs properties provide information specific to this event.

When using the Update method, there are two events that occur per data row updated. The order of execution is as follows:

The event handler receives an argument of type VirtuosoRowUpdatingEventArgs containing data related to this event. The following VirtuosoRowUpdatingEventArgs properties provide information specific to this event.

When using the Update method, there are two events that occur per data row updated. The order of execution is as follows:

The depth of nesting for the current row.

IDataReader.Depth

The outermost table has a depth of zero. The Virtuoso .NET Data Provider does not support nesting and always returns zero.

When not positioned in a valid record set, 0; otherwise the number of columns in the current record. The default is -1.

IDataRecord.FieldCount

After executing a query that does not return rows, FieldCount returns 0.

true if the VirtuosoDataReader is closed; otherwise, false .

IDataReader.IsClosed

IsClosed and RecordsAffected are the only properties that you can call after the VirtuosoDataReader is closed.

Gets the value of the specified column in its native format given the column ordinal.

Gets the value of the specified column in its native format given the column name.

The number of rows changed, inserted, or deleted; 0 if no rows were affected or the statement failed; and -1 for SELECT statements.

IDataReader.RecordsAffected

IsClosed and RecordsAffected are the only properties that you can call after the VirtuosoDataReader is closed.

IDataReader.Close

You must explicitly call the Close method when you are through using the VirtuosoDataReader to use the associated VirtuosoConnection for any other purpose.

The Close method fills in the values for output parameters, return values and RecordsAffected.

A Boolean that is the value of the column.

IDataRecord.GetBoolean

Call IsDBNull to check for null values before calling this method.

The value of the specified column as a byte.

IDataRecord.GetByte

Call IsDBNull to check for null values before calling this method.

The actual number of bytes read.

IDataRecord.GetBytes

GetBytes returns the number of available bytes in the field. In most cases this is the exact length of the field. However, the number returned may be less than the true length of the field if GetBytes has already been used to obtain bytes from the field. This may be the case, for example, if the VirtuosoDataReader is reading a large data structure into a buffer. For more information, see the SequentialAccess setting of System.Data.CommandBehavior in the Microsoft® .NET Framework SDK documentation.

If you pass a buffer that is a null value, GetBytes returns the length of the field in bytes.

The value of the specified column as a character.

IDataRecord.GetChar

Call IsDBNull to check for null values before calling this method.

The actual number of characters read.

IDataRecord.GetChars

GetChars returns the number of available characters in the field. In most cases this is the exact length of the field. However, the number returned may be less than the true length of the field if GetChars has already been used to obtain characters from the field. This may be the case, for example, if the VirtuosoDataReader is reading a large data structure into a buffer. For more information, see the SequentialAccess setting of System.Data.CommandBehavior in the Microsoft® .NET Framework SDK documentation.

If you pass a buffer that is a null value. GetChars returns the length of the field in characters.

IDataRecord.GetData

The name of the source data type.

IDataRecord.GetDataTypeName

The value of the specified column as a DateTime object.

IDataRecord.GetDateTime

Call IsDBNull to check for null values before calling this method.

The value of the specified column as a Decimal object.

IDataRecord.GetDecimal

Call IsDBNull to check for null values before calling this method.

The value of the specified column as a double-precision floating point number.

IDataRecord.GetDouble

Call IsDBNull to check for null values before calling this method.

The Type that is the data type of the object.

IDataRecord.GetFieldType

The value of the specified column as a single-precision floating-point number.

IDataRecord.GetFloat

Call IsDBNull to check for null values before calling this method.

The value of the specified column as a GUID.

IDataRecord.GetGuid

Call IsDBNull to check for null values before calling this method.

The value of the specified column as a 16-bit signed integer.

IDataRecord.GetInt16

Call IsDBNull to check for null values before calling this method.

The value of the specified column as a 32-bit signed integer.

IDataRecord.GetInt32

Call IsDBNull to check for null values before calling this method.

The value of the specified column as a 64-bit signed integer.

IDataRecord.GetInt64

Call IsDBNull to check for null values before calling this method.

A string that is the name of the specified column.

IDataRecord.GetName

The zero-based column ordinal.

IDataRecord.GetOrdinal

A DataTable that describes the column metadata.

IDataReader.GetSchemaTable

For the GetSchemaTable method returns metadata about each column in the following order:

The value of the specified column as a string.

IDataRecord.GetString

Call IsDBNull to check for null values before calling this method.

The value to return.

IDataRecord.GetValue

This method returns DBNull for null database columns.

The number of instances of Object in the array.

IDataRecord.GetValues

For most applications, the GetValues method provides an efficient means for retrieving all columns, rather than retrieving each column individually.

You can pass an Object array that contains fewer than the number of columns contained in the resulting row. Only the amount of data the Object array holds is copied to the array. You can also pass an Object array whose length is more than the number of columns contained in the resulting row.

This method returns DBNull for null database columns.

true if the specified column value is equivalent to DBNull; otherwise, false .

IDataRecord.IsDBNull

To avoid raising an error, call this method to check for null column values before calling the typed Get methods (for example, GetByte, GetChar, and so on).

true if there are more result sets; otherwise, false .

IDataReader.NextResult

Used to process multiple results, which can be generated by executing batch SQL statements.

By default, the VirtuosoDataReader is positioned on the first result.

true if there are more rows; otherwise, false .

IDataReader.Read

The default position of the VirtuosoDataReader is prior to the first record. Therefore, you must call Read to begin accessing any data.

A description of the error.

The five-character error code, which identifies the source of the error.

The total number of errors in the collection.

ICollection.Count

A VirtuosoError that contains the error at the specified index.

ICollection.CopyTo

The collected instances of the VirtuosoError class.

This property is a wrapper for the VirtuosoErrorCollection.

The text describing the error.

This is a wrapper for the Message property of the first VirtuosoError in the Errors property.

The collection of warnings sent from the server.

When you specify an Object in the value parameter, the VirtDbType is inferred from the .NET Framework type of the Object.

The data type, and if appropriate, Size and Precision are inferred from the value of the dbType parameter.

The Size is inferred from the value of the dbType parameter if it is not explicitly set in the size parameter.

The Size is inferred from the value of the dbType parameter if it is not explicitly set in the size parameter.

The Size and Precision are inferred from the value of the dbType parameter if they are not explicitly set in the size and precision parameters.

One of the System.Data.DbType values. The default is String.

IDataParameter.DbType

The VirtDbType and DbType are linked. Therefore, setting the DbType changes the VirtDbType to a supporting VirtDbType.

For a list of the supported data types, see the appropriate VirtDbType member.

One of the System.Data.ParameterDirection values. The default is Input.

IDataParameter.Direction

If the ParameterDirection is Output, and execution of the associated VirtuosoCommand does not return a value, the VirtuosoParameter will contain a null value. Null values are handled using the DBNull class. After the last row from the last resultset is read, the Output, InputOut, and ReturnValue parameters are updated.

true if null values are accepted; otherwise, false . The default is false .

IDataParameter.IsNullable

Null values are handled using the System.DBNull class.

The name of the VirtuosoParameter. The default is an empty string ("").

IDataParameter.ParameterName

Instead of named parameters, the Virtuoso .NET Data Provider uses positional parameters that are marked with a question mark (?) in the syntax of the command text. Parameter objects in the VirtuosoParameterCollection and the actual parameters accepted by the stored procedure or parameterized SQL statement correspond to each other based on the order in which the VirtuosoParameter objects are inserted into the collection rather than by parameter name. Parameter names can be supplied, but will be ignored during parameter object binding.

The maximum number of digits used to represent the Value property. The default value is 0.

IDbDataParameter.Precision

The Precision property is used only for decimal and numeric input parameters.

The number of decimal places to which Value is resolved. The default is 0.

IDbDataParameter.Scale

The Scale property is used only for decimal and numeric input parameters.

The maximum size, in bytes, of the data within the column. The default value is inferred from the parameter value.

IDbDataParameter.Size

The Size property is used for binary and string types.

For variable-length data types, the Size property describes the maximum amount of data to transmit to the server. For example, for a string value, the Size property could be used to limit the amount of data sent to the server to the first one hundred bytes.

For nonstring data types and ANSI string data, the Size property refers to the number of bytes. For Unicode string data, the Size property refers to the number of characters. The count for strings does not include the terminating character.

If not explicitly set, the value of Size is inferred from the actual size of the specified parameter value.

For fixed-width data types, the value of Size is ignored. It can be retrieved for informational purposes, and returns the maximum amount of bytes the provider uses when transmitting the value of the parameter to the server.

The name of the source column that will be used to set the value of this parameter. The default is an empty string ("").

IDataParameter.SourceColumn

When SourceColumn is set to anything other than an empty string, the value of the parameter is retrieved from the column with the SourceColumn name. If Direction is set to Input, the value is taken from the DataSet. If Direction is set to Output, the value is taken from the data source. A Direction of InputOutput is a combination of both.

One of the System.Data.DataRowVersion values. The default is Current.

IDataParameter.SourceVersion

The SourceVersion is used by UpdateCommand during an Update operation to determine whether the parameter value is set to Current or Original. This allows primary keys to be updated. This property is ignored by InsertCommand and DeleteCommand.

This property is set to the version of the DataRow used by either the Item property (DataRow indexer), or the GetChildRows method of the DataRow object.

An Object that is the value of the parameter. The default value is null.

IDataParameter.Value

For input parameters, the value is bound to the VirtuosoCommand that is sent to the server. For output and return-value parameters, the value is set on completion of the VirtuosoCommand and after the VirtuosoDataReader is closed.

When sending a null parameter value to the server, the user must specify DBNull, not null. A null value in the system is an empty object that has no value. DBNull is used to represent null values.

If the application specifies the database type, the bound value is converted to that type when the provider sends the data to the server. The provider attempts to convert any type of value if it supports the IConvertible interface. Conversion errors may result if the specified type is not compatible with the value.

Both the DbType and VirtDbType properties can be inferred by setting Value. If applicable, the size, precision and scale will also be inferred from Value.

The Value property is overwritten by the Update method.

One of the VirtDbType values. The default is NVarChar.

The VirtDbType and DbType are linked. Therefore, setting the DbType changes the VirtDbType to a supporting VirtDbType.

For a list of the supported data types, see the appropriate VirtDbType member. For more information, see "Using Parameters with a DataAdapter" in the Microsoft® .NET Framework SDK documentation.

A string containing the ParameterName.

The number of VirtuosoParameter objects in the collection.

ICollection.Count

Gets or sets the VirtuosoParameter at the specified index.

Gets or sets the VirtuosoParameter with the specified name.

Adds the specified VirtuosoParameter object to the VirtuosoParameterCollection.

Adds the specified VirtuosoParameter object to the VirtuosoParameterCollection.

Adds a VirtuosoParameter to the VirtuosoParameterCollection with the specified parameter name and value.

Adds a VirtuosoParameter to the VirtuosoParameterCollection with the specified parameter name and data type.

Adds a VirtuosoParameter to the VirtuosoParameterCollection with the specified parameter name, data type, and parameter size.

Adds a VirtuosoParameter to the VirtuosoParameterCollection with the specified parameter name, data type, parameter size, and source column name.

IList.Clear

Gets a value indicating whether a VirtuosoParameter object exists in the collection.

Gets a value indicating whether a VirtuosoParameter object with the specified parameter name exists in the collection.

ICollection.CopyTo

Gets the location in the collection of a VirtuosoParameter object.

Gets the location in the collection of the VirtuosoParameter object with the specified parameter name.

IList.Insert

IList.Remove

Removes the VirtuosoParameter at the specified index from the collection.

Removes the VirtuosoParameter with the specified name from the collection.

A copy of the current permission object.

IPermission.Copy

A copy of a permission object represents the same access to resources as the original permission object.

ISecurityEncodable.FromXml

A new permission object that represents the intersection of the current permission object and the specified permission object. This new permission object is a null reference (Nothing in Visual Basic) if the intersection is empty.

IPermission.Intersect

The intersection of two permissions is a permission that describes the set of operations they both describe in common. Only a demand that passes both original permissions will pass the intersection.

true if the current permission object is a subset of the specified permission object; otherwise false .

IPermission.IsSubsetOf

The current permission object is a subset of the specified permission object if the current permission object specifies a set of operations that is wholly contained by the specified permission object. For example, a permission that represents access to C:\example.txt is a subset of a permission that represents access to C:\. If this method returns true, the current permission object represents no more access to the protected resource than does the specified permission object.

true if the VirtuosoPermission instance was created with PermissionState.Unrestricted; otherwise, false .

IUnrestrictedPermission.IsUnrestricted

An XML encoding of the security object, including any state information.

ISecurityEncodable.ToXml

A new permission that represents the union of the current permission and the specified permission.

The result of a call to Union is a permission that represents all the operations represented by both the current permission and the specified permission. Any demand that passes either permission passes their union.

A VirtuosoPermission object.