private static void CompileInsertUpdateClauses(
IStorageDriver storageDriver, DataContainerDescriptor containerDescriptor, RequestExecutionContextCacheInfo cacheInfo, DriverChangeType changeType)
{
var updates = cacheInfo.ParsedRequest.Modify.UpdateAssignments;
var clauses = cacheInfo.ParsedRequest.Modify.InsertUpdateSetClauses;
var fields = cacheInfo.ParsedRequest.Modify.ModifiedFields;
if (clauses.Count != fields.Count)
{
throw new Exception(string.Format("Internal error: insert/update clauses count ({0}) does not match count of modified fields ({1})",
clauses.Count, fields.Count));
}
// compile field assignment clauses (SET clauses or value inserts)
for (var ordinal = 0; ordinal < clauses.Count; ordinal++)
{
var clause = clauses[ordinal];
var field = fields[ordinal];
// for bulk requests, primary key is there but it is only used to lookup the record
// for non-bulk requests, primary key should not be in the list of UPDATE clauses
if (changeType == DriverChangeType.Update && !cacheInfo.ParsedRequest.IsBulk)
{
if (!storageDriver.CanUpdateField(field.FieldId))
{
throw new Exception(string.Format("Cannot update field {0}/{1} on entity {2}", field.FieldId, field.Name, cacheInfo.ParsedRequest.TargetEntity.Name));
}
}
// prepare Action compilation context
var compilerState = QueryParser.PrepareCompilerState(containerDescriptor, cacheInfo, null);
compilerState.CompileToAction = true;
// extractor has signature like Func<ClauseEvaluationContext, T>
var extractor = clause == null
? QueryParser.CompileFieldValueExtractorClause(compilerState, field, containerDescriptor, cacheInfo, MakeNullableType(field.DbType))
: QueryParser.CompileClause(compilerState, clause, containerDescriptor, cacheInfo, MakeNullableType(field.DbType));
// get the value into local variable, to prevent multiple invokations when row writer checks for null
var extractedValue = Expression.Variable(extractor.Type);
// now take the extractor and create another method, that will take the value and then put it into the changebuffer's data
var changeBufferData = Expression.Field(Expression.Field(compilerState.Context, "ChangeBuffer"), "Data");
var blockBody = Expression.Block(
new[] { extractedValue },
Expression.Assign(extractedValue, extractor),
DriverRowData.CreateWriteAccessor(extractedValue, changeBufferData, field.DbType, ordinal));
updates.Add(
new ParsedRequest.FieldAssignment
{
Field = field,
CompiledExpression = (Action <ClauseEvaluationContext>)QueryParser.CompileClause(blockBody, compilerState)
});
}
}
private static void CompileSelectClauses(DataContainerDescriptor containerDescriptor, RequestExecutionContextCacheInfo cacheInfo)
{
var parsedRequest = cacheInfo.ParsedRequest;
if (parsedRequest.IsBulk)
{
foreach (var field in parsedRequest.Select.SelectFields)
{
var exprType = MakeNullableType(field.DbType);
parsedRequest.Select.OutputColumns.Add(
new ParsedRequest.SelectOutputColumn
{
Label = field.Name,
CompiledExpression = QueryParser.CompileFieldValueExtractorClause(field, containerDescriptor, cacheInfo, exprType),
DbType = field.DbType,
IsNullable = exprType.IsNullableType()
});
}
}
else
{
foreach (var clause in parsedRequest.Select.SelectClauses)
{
// under column item, there is a "columnSource" element (with a single child), and optional "Id" element for alias
var columnExpressionNode = clause.RequireChild("columnSource", 0).RequireChild(null, 0);
var compiled = QueryParser.CompileClause(columnExpressionNode, containerDescriptor, cacheInfo, null);
var returnType = compiled.GetType().GetGenericArguments()[1];
var dbType = DriverRowData.DeriveDataType(returnType.GetUnderlyingType());
// get alias
var aliasNode = clause.TryGetChild("Id", 1) ?? columnExpressionNode;
var span = aliasNode.Span;
var label = span.Length > 0
? cacheInfo.CommandText.Substring(span.Location.Position, span.Length)
: aliasNode.FindTokenAndGetText();
parsedRequest.Select.OutputColumns.Add(
new ParsedRequest.SelectOutputColumn
{
Label = label,
CompiledExpression = compiled,
DbType = dbType,
IsNullable = returnType.IsNullableType()
});
}
}
}
