public static void EvaluateLocals(DynamicLinqCommand command)
{
var locals = command.Locals;
if (locals.Count == 0)
{
command.ParamValues = _emptyArray;
return;
}
// evaluate external parameters - they come from OperationContext
var extValues = _emptyArray;
if (command.ExternalParameters != null && command.ExternalParameters.Length > 0)
{
var ctx = command.Session.Context;
extValues = new object[command.ExternalParameters.Length];
for (int i = 0; i < extValues.Length; i++)
{
extValues[i] = LinqExpressionHelper.EvaluateContextParameterExpression(command.Session, command.ExternalParameters[i]);
} //for i
} //if
// evaluate locals
command.ParamValues = new object[locals.Count];
for (int i = 0; i < locals.Count; i++)
{
var local = locals[i];
command.ParamValues[i] = ExpressionHelper.Evaluate(locals[i], command.ExternalParameters, extValues);
}
} //method
private void RewriteCommand(DynamicLinqCommand command)
{
_model = command.Session.Context.App.Model;
_command = command;
_locals = command.Locals;
//create parameters
_parameters = new List <ParameterExpression>();
for (int i = 0; i < _locals.Count; i++)
{
var local = _locals[i];
var prm = local.NodeType == ExpressionType.Parameter ? (ParameterExpression)local : Expression.Parameter(local.Type, "@P" + i);
_parameters.Add(prm);
}
var body = this.Visit(_command.QueryExpression);
_command.Lambda = Expression.Lambda(body, _parameters);
}
private void AnalyzeCommand(DynamicLinqCommand command)
{
_command = command;
_model = command.Session.Context.App.Model;
_cacheKeyBuilder = new SqlCacheKeyBuilder("Linq", command.Kind.ToString(), command.Operation.ToString());
try {
AnalyzeNode(_command.QueryExpression);
//copy some values to command
command.SqlCacheKey = _cacheKeyBuilder.Key;
command.EntityTypes = _entityTypes;
command.LockType = _lockType;
command.Includes = _includes;
command.Options |= _options;
command.Locals.AddRange(_locals);
command.ExternalParameters = _externalParams?.ToArray();
if (command.Locals.Count > 0)
{
LinqExpressionHelper.EvaluateLocals(command);
}
} catch (Exception ex) {
ex.Data["LinqExperssion"] = _command.QueryExpression + string.Empty;
throw;
}
}
public SqlStatement TranslateNonQuery(DynamicLinqCommand command)
{
var translCtx = new TranslationContext(_dbModel, command);
// convert lambda params into an initial set of ExternalValueExpression objects;
foreach (var prm in command.Lambda.Parameters)
{
var inpParam = new ExternalValueExpression(prm);
translCtx.ExternalValues.Add(inpParam);
}
//Analyze/transform base select query
var selectExpr = TranslateSelectExpression(command, translCtx);
var targetEnt = command.UpdateEntity;
var targetTable = _dbModel.GetTable(targetEnt.EntityType);
var nonQueryCmd = new NonQueryLinqCommand(command, targetTable, selectExpr);
// Analyze base query output expression
var targetTableExpr = new TableExpression(targetTable);
var readerBody = selectExpr.RowReaderLambda.Body;
switch (nonQueryCmd.Operation)
{
case LinqOperation.Update:
case LinqOperation.Insert:
Util.Check(readerBody.NodeType == ExpressionType.New,
"Query for LINQ {0} command must return New object", nonQueryCmd.Operation);
var newExpr = readerBody as NewExpression;
var outValues = selectExpr.Operands.ToList();
for (int i = 0; i < newExpr.Members.Count; i++)
{
var memberName = newExpr.Members[i].Name;
var memberInfo = targetEnt.GetMember(memberName);
Util.Check(memberInfo != null, "Member {0} not found in entity {1}.", memberName, targetEnt, targetEnt.EntityType);
switch (memberInfo.Kind)
{
case EntityMemberKind.Column:
var col = _translator.CreateColumnForMember(targetTableExpr, memberInfo, translCtx);
nonQueryCmd.TargetColumns.Add(col.ColumnInfo);
nonQueryCmd.SelectOutputValues.Add(outValues[i]);
break;
case EntityMemberKind.EntityRef:
var fromKey = memberInfo.ReferenceInfo.FromKey;
Util.Check(fromKey.ExpandedKeyMembers.Count == 1,
"References with composite keys are not supported in LINQ non-query operations. Reference: ", memberName);
var pkMember = fromKey.ExpandedKeyMembers[0].Member;
var col2 = _translator.CreateColumnForMember(targetTableExpr, pkMember, translCtx);
nonQueryCmd.TargetColumns.Add(col2.ColumnInfo);
nonQueryCmd.SelectOutputValues.Add(outValues[i]);
break;
default:
Util.Throw("Property cannot be used in the context: {0}.", memberName);
break;
}
}
break;
case LinqOperation.Delete:
nonQueryCmd.SelectOutputValues.Add(readerBody); //should return single value - primary key
break;
}
// Build SQL
var sqlBuilder = _dbModel.Driver.CreateLinqNonQuerySqlBuilder(_dbModel, nonQueryCmd);
var stmt = sqlBuilder.BuildLinqNonQuerySql();
return(stmt);
} //method
public static void Analyze(DynamicLinqCommand command)
{
var scanner = new LinqCommandAnalyzer();
scanner.AnalyzeCommand(command);
}
public static void RewriteToLambda(DynamicLinqCommand command)
{
var rewriter = new LinqCommandRewriter();
rewriter.RewriteCommand(command);
}
