See SQL From EntityFramework with Collection-like Queries - sql

Question

I do not have 'full' the version of MS SQL (SQL Express 2008) so I do not have the profiler tool.
I want to see the SQL generated by my Entity Framework code, but all of the examples I find use the
var x = from u in table
select u;
type of syntax; But most of my queries are more like ..
var x = context.Users.Single(n => n.Name == "Steven");
type of syntax. What can I do to see the SQL generated, from this manner of coding? Any ideas?

Answer 1

check out this link... it has a tracing provider for EF4.
I'll try to give an example based on how I'm using this in a unit test.
Step 1: Register the provider
There are a couple ways to configure the provider. For my unit tests I configured the provider in code by calling the static method RegisterProvider();
[AssemblyInitialize()]
public static void AssemblyInit(TestContext context) {
EFTracingProviderConfiguration.RegisterProvider();
}
Step 2: Create a sub-class of your entity model to provide the tracing extensions
public partial class ExtendedNorthwindEntities : NorthwindEntities {
private TextWriter logOutput;
public ExtendedNorthwindEntities(string connectionString)
: base(EntityConnectionWrapperUtils.CreateEntityConnectionWithWrappers(
connectionString,
"EFTracingProvider")) {
}
#region Tracing Extensions
private EFTracingConnection TracingConnection {
get { return this.UnwrapConnection<EFTracingConnection>(); }
}
public event EventHandler<CommandExecutionEventArgs> CommandExecuting {
add { this.TracingConnection.CommandExecuting += value; }
remove { this.TracingConnection.CommandExecuting -= value; }
}
public event EventHandler<CommandExecutionEventArgs> CommandFinished {
add { this.TracingConnection.CommandFinished += value; }
remove { this.TracingConnection.CommandFinished -= value; }
}
public event EventHandler<CommandExecutionEventArgs> CommandFailed {
add { this.TracingConnection.CommandFailed += value; }
remove { this.TracingConnection.CommandFailed -= value; }
}
private void AppendToLog(object sender, CommandExecutionEventArgs e) {
if (this.logOutput != null) {
this.logOutput.WriteLine(e.ToTraceString().TrimEnd());
this.logOutput.WriteLine();
}
}
public TextWriter Log {
get { return this.logOutput; }
set {
if ((this.logOutput != null) != (value != null)) {
if (value == null) {
CommandExecuting -= AppendToLog;
}
else {
CommandExecuting += AppendToLog;
}
}
this.logOutput = value;
}
}
#endregion
}
Step 3: Attach to the Log property
var context = new ExtendedNorthwindEntities("name=\"NorthwindEntities\"");
context.Log = System.Console.Out;

Answer 2

Does Express Edition support extended events? If so this will capture statement and sp completed events in a similar way to Profiler.
Edit: I have changed it to use a memory target rather than a file target. Ideally uncomment the WHERE sections and replace with an appropriate user name to capture only events of interest or you can filter by spid with WHERE (([sqlserver].[session_id]=(56))) for example.
IF EXISTS(SELECT * FROM sys.server_event_sessions WHERE name='test_trace')
DROP EVENT SESSION [test_trace] ON SERVER;
CREATE EVENT SESSION [test_trace]
ON SERVER
ADD EVENT sqlserver.sp_statement_completed(
ACTION (package0.callstack, sqlserver.session_id, sqlserver.sql_text)
-- WHERE (([sqlserver].[username]='Domain\Username'))
),
ADD EVENT sqlserver.sql_statement_completed(
ACTION (package0.callstack, sqlserver.session_id, sqlserver.sql_text)
--WHERE (([sqlserver].[username]='Domain\Username'))
)
ADD TARGET package0.ring_buffer
WITH (MAX_MEMORY = 4096KB, EVENT_RETENTION_MODE = ALLOW_SINGLE_EVENT_LOSS,
MAX_DISPATCH_LATENCY = 1 SECONDS, MAX_EVENT_SIZE = 0KB,
MEMORY_PARTITION_MODE = NONE, TRACK_CAUSALITY = OFF, STARTUP_STATE = OFF)
ALTER EVENT SESSION [test_trace] ON SERVER STATE = START
And to review the results (Query generated using Adam Machanic's XE Code Generator)
DECLARE
#session_name VARCHAR(200) = 'test_trace'
SELECT
pivoted_data.*
FROM
(
SELECT MIN(event_name) AS event_name,
MIN(event_timestamp) AS event_timestamp,
unique_event_id,
CONVERT ( BIGINT, MIN (
CASE
WHEN d_name = 'cpu'
AND d_package IS NULL
THEN d_value
END ) ) AS [cpu],
CONVERT ( BIGINT, MIN (
CASE
WHEN d_name = 'duration'
AND d_package IS NULL
THEN d_value
END ) ) AS [duration],
CONVERT ( BIGINT, MIN (
CASE
WHEN d_name = 'object_id'
AND d_package IS NULL
THEN d_value
END ) ) AS [object_id],
CONVERT ( INT, MIN (
CASE
WHEN d_name = 'object_type'
AND d_package IS NULL
THEN d_value
END ) ) AS [object_type],
CONVERT ( DECIMAL(28,0), MIN (
CASE
WHEN d_name = 'reads'
AND d_package IS NULL
THEN d_value
END ) ) AS [reads],
CONVERT ( VARCHAR(MAX), MIN (
CASE
WHEN d_name = 'session_id'
AND d_package IS NOT NULL
THEN d_value
END ) ) AS [session_id],
CONVERT ( INT, MIN (
CASE
WHEN d_name = 'source_database_id'
AND d_package IS NULL
THEN d_value
END ) ) AS [source_database_id],
CAST((SELECT CONVERT ( VARCHAR(MAX), MIN (
CASE
WHEN d_name = 'sql_text'
AND d_package IS NOT NULL
THEN d_value
END ) ) AS [processing-instruction(x)] FOR XML PATH('') ) AS XML) AS [sql_text],
CONVERT ( DECIMAL(28,0), MIN (
CASE
WHEN d_name = 'writes'
AND d_package IS NULL
THEN d_value
END ) ) AS [writes]
FROM
(
SELECT
*,
CONVERT(VARCHAR(400), NULL) AS attach_activity_id
FROM
(
SELECT
event.value('(#name)[1]', 'VARCHAR(400)') as event_name,
event.value('(#timestamp)[1]', 'DATETIME') as event_timestamp,
DENSE_RANK() OVER (ORDER BY event) AS unique_event_id,
n.value('(#name)[1]', 'VARCHAR(400)') AS d_name,
n.value('(#package)[1]', 'VARCHAR(400)') AS d_package,
n.value('((value)[1]/text())[1]', 'VARCHAR(MAX)') AS d_value,
n.value('((text)[1]/text())[1]', 'VARCHAR(MAX)') AS d_text
FROM
(
SELECT
(
SELECT
CONVERT(xml, target_data)
FROM sys.dm_xe_session_targets st
JOIN sys.dm_xe_sessions s ON
s.address = st.event_session_address
WHERE
s.name = #session_name
AND st.target_name = 'ring_buffer'
) AS [x]
FOR XML PATH(''), TYPE
) AS the_xml(x)
CROSS APPLY x.nodes('//event') e (event)
CROSS APPLY event.nodes('*') AS q (n)
) AS data_data
) AS activity_data
GROUP BY
unique_event_id
) AS pivoted_data;