cppstddb

A reference implementation for a modern C++ database client interface.

Status

This is an early stage project and it needs a lot of work before it is ready for serious use. Basic support now exists for mysql, postgres, and sqlite. More soon.

Planned Design Highlights (WIP)

• A database and driver neutral interface specification
• Reference counted value objects provide ease of use
• A header only design
• Support for direct and polymorphic interfaces
• Range-based for loop support
• Range V3 support
• A fluent style interface
• URL style connection strings
• Reference implementations: ODBC, sqlite, mysql, oracle, postgres, freetds (MS SQL)
• Scalar & array input binding
• Internally managed output binding
• Connection pooling

Usage

This is a header only library. Just add the src directory to your include path. The only requirements are a C++ 17 compiler and any dependences that the underlying database driver requires. You will also need to ensure that the underlying database client library is installed (libmysql for mysql, for example) in your environment.

Here is a simple Unix GCC compile/run example:

g++ -c db_demo.cpp -std=c++1y -I$HOME/src/cppstddb/src
g++ -o db_demo db_demo.o -lpthread -lmysqlclient
./db_demo

The runtime logging level is warn (which includes ERROR and WARN levels), but can be raised to include higher logging levels (INFO,DEBUG,TRACE) by setting the CPPSTDDB_LOG_LEVEL environment variable. Example:

export CPPSTDDB_LOG_LEVEL=TRACE

Examples

simple query write to stdout

using namespace cppstddb::mysql;

auto db = cppstddb::mysql::create_database();
db
    .statement("select * from score")
    .query()
    .rows()
    .write(cout);

simple range-based for loop example

auto db = cppstddb::mysql::create_database();
auto rowset = db.connection().statement("select * from score").query().rows();
for(auto row : rowset) {
    auto f = row[0];
    std::cout << f << "\n";
}

use of standard algorithm / lambda

auto db = cppstddb::mysql::create_database();
auto r = db.statement("select name,score from score").query().rows();

auto key = "b";
auto i = find_if(r.begin(), r.end(), [key](auto row) { 
        return row[0].str() == key; });
assert(i != r.end());
auto row = *i;
cout << row["name"] << ":" << row["score"] << "\n";

The Test Suite

The test suite is a set of templated test cases for use in testing the the direct drivers. Currently, it does not use a test framework just to keep the dependency factor low and uses ninja as the build tool (subject to change)

The tests are run in a database named 'cppstddb' which must exist in the database. Running the test suite does drop and create tables each time is is run, so treat with care.

Running the test suite (mysql example):

ninja -C test/mysql