postgresql - Why does my LIKE statement fail with '\\_' for matching? -


i have database entry has entries this:

id | name | code_set_id

i have particular entry need find:

 674272310 | raphodo/qrc_resources.py |      782732

in rails app (2.3.8), have statement evaluates this:

select * fyles code_set_id = 782732 , name 'raphodo/qrc\\_resources.py%';

from reading on escaping, above query correct. supposed correctly double escape underscore. query not find record in database. these queries will:

select * fyles code_set_id = 782732 , name 'raphodo/qrc\_resources.py%';  select * fyles code_set_id = 782732 , name 'raphodo/qrc_resources.py%';

am missing here? why first sql statement not finding correct entry?

a single backslash in rhs of like escapes following character:

9.7.1. like
[...]
match literal underscore or percent sign without matching other characters, respective character in pattern must preceded escape character. default escape character backslash different 1 can selected using escape clause. match escape character itself, write 2 escape characters.

so literal underscore in pattern:

\_

and single backslash followed "any character" pattern:

\\_

you want see this:

raphodo/qrc\_resources.py%

postgresql used interpret c-stye backslash escapes in strings default no longer, have use e'...' use backslash escapes in string literals (unless you've changed configuration options). string constants c-style escapes section of manual covers simple version these two:

name e'raphodo/qrc\\_resources.py%' name 'raphodo/qrc\_resources.py%'

do same thing of postgresql 9.1.

presumably rails 2.3.8 app (or whatever preparing patterns) assuming older version of postgresql 1 you're using. you'll need adjust things not double backslashes (or prefix pattern string literals es).


Comments

Post a Comment

Popular posts from this blog

How to put a lock and transaction on table using spring 4 or above using jdbcTemplate and annotations like @Transactional? -

i trying put lock on table while writing on table , if happened in between roll-back . trying convert below code lock table test_g1 read; lock table test_g write; -- begin; start transaction; insert test_g1 values(143); insert test_g values(145); select * test_g1; select * test_g; rollback; select * test_g; unlock tables; how convert above code @transactional spring jdbctemplate code? @transactional(rollbackfor={dataaccessexception.class}) public void test(){ jdbctemplate.execute("insert test1 (id, nam) values (4, 'a')"); throw new dataaccessexception("error") { }; } here trying throw error, insert statement should rollback it's not happening . thanks edit-1 attaching code , doing in jdbcdaoimpl.java , mentioned problem comment above test() . app.java package com.cgiri.javabrains.spring4; import org.springframework.beans.factory.annotation.autowired; import org.springframework.context.applic...
Read more

c# - Update a combobox from a presenter (MVP) -

i using mvp in project, new in mvp. have 2 comboboxes. when select option in combobox, combobox should filled new data. this action in presenter. view 'view1' in presenter, , introduced combobox1 , combobox2 properties in 'view1', because need 'datasource', 'displaymember', 'valuemember' , 'refresh()' in method below. but, when using pattern, enough send property like public string combobox2 { { return combobox1.selectedvalue.tosstring(); } } into presenter not whole combobox. how can solve problem? public void onselectedindexchangedcombobox1() { if (view1.combobox1.selectedindex == -1) { return; } datatable dt = tools.getdatatable("a path"); var query = (from o in dt.asenumerable() o.field<string>("afield") == farmerview.combobox1.selectedvalue.tostring() orderby o.field<string>("anotherfield") select...
Read more

How to understand 2 main() functions after using uftrace to profile the C++ program? -

i trying uftrace profile following simple c++ program: #include <iostream> class { public: a() {std::cout << "a created" << std::endl;} ~a() {std::cout << "a destroyed" << std::endl;} }; int main() { a; return 0; } the profile result this: # uftrace a.out created destroyed # duration tid function 2.026 [ 4828] | __cxa_atexit(); [ 4828] | main() { [ 4828] | __static_initialization_and_destruction_0() { 89.397 [ 4828] | std::ios_base::init::init(); 0.768 [ 4828] | __cxa_atexit(); 93.029 [ 4828] | } /* __static_initialization_and_destruction_0 */ 94.425 [ 4828] | } /* main */ [ 4828] | main() { [ 4828] | a::a() { 11.104 [ 4828] | std::operator <<(); 10.825 [ 4828] | std::basic_ostream::operator <<(); 24.514 [ 4828] | } /* a::a */ [ 4828] | a::~a() { 0.978 [ 4828] | ...
Read more