Calling Stored Procedures
You can invoke a stored procedure using PrestoCommand in the same way as any other SQL stored procedure. To instantiate a PrestoCommand object, provide the name of the stored procedure and a PrestoConnection instance as arguments to the constructor. Set the value of the CommandType property to "StoredProcedure" and add the parameters as key-value pairs to the Parameters collection of the PrestoCommand instance.
C#
string connectionString = "Server=127.0.0.1;Port=8080;"; using (PrestoConnection connection = new PrestoConnection(connectionString)) { PrestoCommand cmd = new PrestoCommand("CreateTable", connection); cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.Add(new PrestoParameter("@TableName", "Orders")); // Add other parameters as needed ... PrestoDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { for (int i = 0; i < rdr.FieldCount; i++) { Console.WriteLine(rdr.GetName(i) + " --> " + rdr[i]); } Console.WriteLine(); } }
VB.NET
Dim connectionString As String = "Server=127.0.0.1;Port=8080;" Using connection As New PrestoConnection(connectionString) Dim cmd As New PrestoCommand("CreateTable", connection) cmd.CommandType = CommandType.StoredProcedure cmd.Parameters.Add(New PrestoParameter("@TableName", "Orders")) ' Add other parameters as needed ... Dim rdr As PrestoDataReader = cmd.ExecuteReader() While rdr.Read() For i As Integer = 0 To rdr.FieldCount - 1 Console.WriteLine(rdr.GetName(i) + " --> " + rdr(i)) Next Console.WriteLine() End While End Using
Alternatively, you can set the parameters of a stored procedure in the text of the command. The support for stored procedure statements follows the standard form shown below:
"EXECUTE my_proc @first = 1, @second = 2, @third = 3;" "EXEC my_proc @first = 1, @second = 2, @third = 3;"
To execute a parameterized query, add parameters as key-value pairs to the Parameters collection of the PrestoCommand instance.
C#
string connectionString = "Server=127.0.0.1;Port=8080;"; using (PrestoConnection connection = new PrestoConnection(connectionString)) { PrestoCommand cmd = new PrestoCommand("EXECUTE CreateTable TableName = @TableName;", connection); cmd.Parameters.Add(new PrestoParameter("@TableName", "Orders")); // Add other parameters as needed ... PrestoDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { for (int i = 0; i < rdr.FieldCount; i++) { Console.WriteLine(rdr.GetName(i) + " --> " + rdr[i]); } Console.WriteLine(); } }
VB.NET
Dim connectionString As String = "Server=127.0.0.1;Port=8080;" Using connection As New PrestoConnection(connectionString) Dim cmd As New PrestoCommand("EXECUTE CreateTable TableName = @TableName;", connection) cmd.Parameters.Add(New PrestoParameter("@TableName", "Orders")) ' Add other parameters as needed ... Dim rdr As PrestoDataReader = cmd.ExecuteReader() While rdr.Read() For i As Integer = 0 To rdr.FieldCount - 1 Console.WriteLine(rdr.GetName(i) + " --> " + rdr(i)) Next Console.WriteLine() End While End Using