Prepare Method
Creates a prepared (or compiled) version of the command on the data source.
Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)
Syntax
'Declaration
Public Overrides Sub Prepare
'Usage
Dim instance As SqlCeCommand
instance.Prepare()
public override void Prepare()
public:
virtual void Prepare() override
abstract Prepare : unit -> unit
override Prepare : unit -> unit
public override function Prepare()
Implements
IDbCommand. . :: . .Prepare() () () ()
Exceptions
| Exception | Condition |
|---|---|
| InvalidOperationException | The Connection is not set. -or - The Connection is not Open. |
Remarks
If the CommandType property is set to TableDirect, Prepare does nothing.
Before you call Prepare, specify the data type of each parameter in the statement to be prepared. For each parameter that has a variable-length data type, you must set the Size property to the maximum size needed. Prepare returns an error if these conditions are not met.
If you call an Execute method after calling Prepare, any parameter value that is larger than the value specified by the Size property is automatically truncated to the original specified size of the parameter, and no truncation errors are returned.
Examples
Dim conn As New SqlCeConnection("Data Source = MyDatabase.sdf;")
conn.Open()
Dim command As SqlCeCommand = conn.CreateCommand()
' Create and prepare a SQL statement
'
command.CommandText = "INSERT INTO Region (RegionID, RegionDescription) VALUES (@id, @desc)"
Dim param As SqlCeParameter = Nothing
' NOTE:
' For optimal performance, make sure you always set the parameter
' type and the maximum size - this is especially important for non-fixed
' types such as NVARCHAR or NTEXT; In case of named parameters,
' SqlCeParameter instances do not need to be added to the collection
' in the order specified in the query; If however you use ? as parameter
' specifiers, then you do need to add the parameters in the correct order
'
param = New SqlCeParameter("@id", SqlDbType.Int)
command.Parameters.Add(param)
param = New SqlCeParameter("@desc", SqlDbType.NVarChar, 100)
command.Parameters.Add(param)
command.Parameters("@desc").Size = 100
' Calling Prepare after having set the CommandText and parameters
'
command.Prepare()
' Execute the SQL statement
'
command.ExecuteNonQuery()
' Change parameter values and call ExecuteNonQuery again
'
command.Parameters(0).Value = 21
command.Parameters(1).Value = "mySecondRegion"
command.ExecuteNonQuery()
SqlCeConnection conn = new SqlCeConnection("Data Source = MyDatabase.sdf;");
conn.Open();
SqlCeCommand command = conn.CreateCommand();
// Create and prepare a SQL statement
//
command.CommandText = "INSERT INTO Region (RegionID, RegionDescription) VALUES (@id, @desc)";
SqlCeParameter param = null;
// NOTE:
// For optimal performance, make sure you always set the parameter
// type and the maximum size - this is especially important for non-fixed
// types such as NVARCHAR or NTEXT; In case of named parameters,
// SqlCeParameter instances do not need to be added to the collection
// in the order specified in the query; If however you use ? as parameter
// specifiers, then you do need to add the parameters in the correct order
//
param = new SqlCeParameter("@id", SqlDbType.Int);
command.Parameters.Add(param);
param = new SqlCeParameter("@desc", SqlDbType.NVarChar, 100);
command.Parameters.Add(param);
command.Parameters["@desc"].Size = 100;
// Calling Prepare after having set the CommandText and parameters
//
command.Prepare();
// Execute the SQL statement
//
command.ExecuteNonQuery();
// Change parameter values and call ExecuteNonQuery again
//
command.Parameters[0].Value = 21;
command.Parameters[1].Value = "mySecondRegion";
command.ExecuteNonQuery();