mirror of
https://github.com/rbock/sqlpp11.git
synced 2024-12-24 06:41:04 +08:00
993ddcc049
Copied wiki into docs directory This allows developers to open pull requests to edit documentation and also use mkdocs to create a styled HTML version * changed wiki links to relative links * removed Planned-Features.md * removed reference to planned features in Home.md
59 lines
1.9 KiB
Markdown
59 lines
1.9 KiB
Markdown
# New Features
|
|
|
|
There are a bunch of new features, that are not fully documented yet. If you would like to contribute documentation, please let me know.
|
|
|
|
## Preprocessor generator for columns/tables
|
|
You'll need boost 1.50 or greater to use this feature by niXman:
|
|
|
|
```C++
|
|
#include <sqlpp11/ppgen.h>
|
|
SQLPP_DECLARE_TABLE(
|
|
(tab_person)
|
|
,
|
|
(id , int , SQLPP_AUTO_INCREMENT)
|
|
(name , varchar(255), SQLPP_NOT_NULL )
|
|
(feature, int , SQLPP_NOT_NULL )
|
|
)
|
|
```
|
|
|
|
See `examples/ppgen.hpp`.
|
|
|
|
## Union
|
|
Unions are now supported. The arguments need to have the same names and types in their columns.
|
|
|
|
```C++
|
|
db(select(t.alpha).from(t).where(true)
|
|
.union_distinct(select(f.epsilon.as(t.alpha)).from(f).where(true)));
|
|
db(select(t.alpha).from(t).where(true)
|
|
.union_all(select(f.epsilon.as(t.alpha)).from(f).where(true)));
|
|
```
|
|
|
|
## With
|
|
sqlpp11 supports common table expressions:
|
|
|
|
```C++
|
|
auto x = sqlpp::cte(sqlpp::alias::x).as(select(all_of(t)).from(t));
|
|
|
|
db(with(x)(select(x.alpha).from(x).where(true)));
|
|
```
|
|
## Custom Queries
|
|
This allows you to combine building blocks of sqlpp11 into custom queries, for instance a SELECT..INTO which is not supported yet.
|
|
|
|
```C++
|
|
// A custom (select ... into) with adjusted return type
|
|
// The first argument with a return type is the select,
|
|
// but the custom query is really an insert. Thus, we tell it so.
|
|
db(custom_query(select(all_of(t)).from(t), into(f))
|
|
.with_result_type_of(insert_into(f)));
|
|
```
|
|
|
|
## Schema-qualified tables
|
|
sqlpp11 assumes that you're connection addresses one database, normally. But you can tell it about other databases using the `sqlpp::schema_t` and instantiating schema-qualified tables with it:
|
|
|
|
```C++
|
|
auto schema = db.attach("lorem_ipsum");
|
|
auto s = schema_qualified_table(schema, TabSample{}).as(sqlpp::alias::x)
|
|
// s now represents "lorem_ipsum.tab_sample as x"
|
|
// s can be used like any other table in the code
|
|
```
|