The SOCI PostgreSQL backend is supported for use with PostgreSQL >= 7.3, although versions older than 8.0 will suffer from limited feature support. See below for details.
|PostgreSQL version||Operating System||Compiler|
|8.3||Mac OS X 10.5.3||g++ 4.0.1|
|8.3||Mac OS X 10.5.3||g++ 4.4.0|
|8.3||FreeBSD 7.0||g++ 4.2.1|
|8.3||Linux i686 2.6.9 (RedHat family)||g++ 3.4.6|
|8.2.7||Linux i686 2.6.23 (Fedora release 7)||g++ 4.1.2|
The SOCI PostgreSQL backend requires PostgreSQL's
libpq client library.
Note that the SOCI library itself depends also on
libdl, so the minimum set of libraries needed to compile a basic client program is:
-lsoci_core -lsoci_postgresql -ldl -lpq
To establish a connection to the PostgreSQL database, create a
postgresql backend factory together with a connection string:
session sql(postgresql, "dbname=mydatabase"); // or: session sql("postgresql", "dbname=mydatabase"); // or: session sql("postgresql://dbname=mydatabase");
The set of parameters used in the connection string for PostgreSQL is the same as accepted by the
PQconnectdb function from the
Once you have created a
session object as shown above, you can use it to access the database, for example:
int count; sql << "select count(*) from invoices", into(count);
The PostgreSQL backend supports the use of the SOCI
row class, which facilitates retrieval of data whose type is not known at compile time.
row::get<T>(), the type you should pass as
T depends upon the underlying database type.
For the PostgreSQL backend, this type mapping is:
|PostgreSQL Data Type||SOCI Data Type||
|numeric, real, double||
|boolean, smallint, integer||
|char, varchar, text, cstring, bpchar||
|abstime, reltime, date, time, timestamp, timestamptz, timetz||
(See the dynamic resultset binding documentation for general information on using the
int id = 7; sql << "select name from person where id = :id", use(id, "id")
Apart from the portable "colon-name" syntax above, which is achieved by rewriting the query string, the backend also supports the PostgreSQL native numbered syntax:
int i = 7; int j = 8; sql << "insert into t(x, y) values($1, $2)", use(i), use(j);
The use of native syntax is not recommended, but can be nevertheless imposed by switching off the query rewriting. This can be achieved by defining the macro
SOCI_PGSQL_NOBINDBYNAME and it is actually necessary for PostgreSQL 7.3, in which case binding of use elements is not supported at all. See the Configuration options section for details.
The PostgreSQL backend has full support for SOCI's bulk operations interface.
Transactions are also fully supported by the PostgreSQL backend.
The PostgreSQL backend supports working with data stored in columns of type Blob, via SOCI's
blob class with the exception that trimming is not supported.
The concept of row identifier (OID in PostgreSQL) is supported via SOCI's rowid class.
Nested statements are not supported by PostgreSQL backend.
PostgreSQL stored procedures can be executed by using SOCI's procedure class.
SOCI provides access to underlying datbabase APIs via several
get_backend() functions, as described in the beyond SOCI documentation.
The PostgreSQL backend provides the following concrete classes for navite API access:
|Accessor Function||Concrete Class|
To support older PostgreSQL versions, the following configuration macros are recognized:
SOCI_PGSQL_NOBINDBYNAME- switches off the query rewriting.
SOCI_PGSQL_NOPARAMS- disables support for parameterized queries (binding of use elements), automatically imposes also the
SOCI_PGSQL_NOBINDBYNAMEmacro. It is necessary for PostgreSQL 7.3.
SOCI_PGSQL_NOPREPARE- disables support for separate query preparation, which in this backend is significant only in terms of optimization. It is necessary for PostgreSQL 7.3 and 7.4.
Copyright © 2004-2009 Maciej Sobczak, Stephen Hutton