internal static Expression GetInsertExpression(ISyntaxProvider syntax, Expression instance)
{
InsertCommandExpression insertExp;
var entityType = instance.Type;
Func <TableExpression, IEnumerable <ColumnAssignment> > func;
if (instance is ParameterExpression parExp)
{
func = new Func <TableExpression, IEnumerable <ColumnAssignment> >(t => GetInsertArguments(syntax, t, parExp));
}
else
{
var entity = instance.As <ConstantExpression>().Value as IEntity;
func = new Func <TableExpression, IEnumerable <ColumnAssignment> >(t => GetInsertArguments(syntax, t, entity));
}
var metadata = EntityMetadataUnity.GetEntityMetadata(entityType);
var table = new TableExpression(new TableAlias(), metadata.TableName, entityType);
insertExp = new InsertCommandExpression(table, func(table))
{
WithAutoIncrement = !string.IsNullOrEmpty(syntax.IdentitySelect) && HasAutoIncrement(instance.Type)
};
return(insertExp);
}
protected override Expression VisitInsert(InsertCommandExpression insert)
{
if (insert.Assignments.Count == 0)
{
return(Expression.Constant(-1));
}
var arguments = VisitColumnAssignments(insert.Assignments);
insert = insert.Update(insert.Table, arguments);
return(insert.WithAutoIncrement ? BuildExecuteScalarCommand(insert) :
BuildExecuteNoQueryCommand(insert));
}
/// <summary>
/// 访问 <see cref="InsertCommandExpression"/> 表达式。
/// </summary>
/// <param name="insert"></param>
/// <returns></returns>
protected override Expression VisitInsert(InsertCommandExpression insert)
{
_isAsync = _isAsync || insert.IsAsync;
//如果没有更新参数，则返回-1
if (insert.Assignments.Count == 0)
{
return(_isAsync ? Expression.Constant(Task.FromResult(-1)) : Expression.Constant(-1));
}
var arguments = VisitColumnAssignments(insert.Assignments);
insert = insert.Update(insert.Table, arguments);
return(insert.WithAutoIncrement ? BuildExecuteScalarCommand(insert) :
BuildExecuteNoQueryCommand(insert));
}
