diff options
Diffstat (limited to 'section')
| -rw-r--r-- | section/README | 63 | ||||
| -rw-r--r-- | section/database.hxx | 94 | ||||
| -rw-r--r-- | section/driver.cxx | 133 | ||||
| -rw-r--r-- | section/makefile | 122 | ||||
| -rw-r--r-- | section/person.hxx | 105 |
5 files changed, 517 insertions, 0 deletions
diff --git a/section/README b/section/README new file mode 100644 index 0000000..34be589 --- /dev/null +++ b/section/README @@ -0,0 +1,63 @@ +This example shows how to use object sections to implement lazy-loading +and change-updating of a subset of data members in a persistent class. + +The example consists of the following files: + +person.hxx + Header file defining the 'person' persistent class. It contains a number of + data members some of which are made to belong to a section. + +person-odb.hxx +person-odb.ixx +person-odb.cxx +person.sql + The first three files contain the database support code and the last file + contains the database schema for the person.hxx header. + + These files are generated by the ODB compiler from person.hxx using the + following command line: + + odb -d <database> --generate-schema person.hxx + + Where <database> stands for the database system we are using, for example, + 'mysql'. + +database.hxx + Contains the create_database() function which instantiates the concrete + database class corresponding to the database system we are using. + +driver.cxx + Driver for the example. It includes the person.hxx and person-odb.hxx + headers to gain access to the persistent classes and their database support + code. It also includes database.hxx for the create_database() function + declaration. + + In main() the driver first calls create_database() to obtain the database + instance. It then persists a 'person' object, loads it back, including + the section, and prints the contents of its members. Finally, the driver + shows how to update the state of the section data members in various ways, + then re-loads and prints the object to verify that the changes have been + made persistent. + +To compile and link the example manually from the command line we can use +the following commands (using MySQL as an example; replace 'c++' with your +C++ compiler name): + +c++ -c person-odb.cxx +c++ -DDATABASE_MYSQL -c driver.cxx +c++ -o driver driver.o person-odb.o -lodb-mysql -lodb + +To run the example we may first need to create the database schema (for some +database systems, such as SQLite, the schema is embedded into the generated +code which makes this step unnecessary). Using MySQL as an example, this +can be achieved with the following command: + +mysql --user=odb_test --database=odb_test < person.sql + +Here we use 'odb_test' as the database login and also 'odb_test' as the +database name. + +Once the database schema is ready, we can run the example (using MySQL as +the database): + +./driver --user odb_test --database odb_test diff --git a/section/database.hxx b/section/database.hxx new file mode 100644 index 0000000..4a1a350 --- /dev/null +++ b/section/database.hxx @@ -0,0 +1,94 @@ +// file : section/database.hxx +// copyright : not copyrighted - public domain + +// +// Create concrete database instance based on the DATABASE_* macros. +// + +#ifndef DATABASE_HXX +#define DATABASE_HXX + +#include <string> +#include <memory> // std::auto_ptr +#include <cstdlib> // std::exit +#include <iostream> + +#include <odb/database.hxx> + +#if defined(DATABASE_MYSQL) +# include <odb/mysql/database.hxx> +#elif defined(DATABASE_SQLITE) +# include <odb/connection.hxx> +# include <odb/transaction.hxx> +# include <odb/schema-catalog.hxx> +# include <odb/sqlite/database.hxx> +#elif defined(DATABASE_PGSQL) +# include <odb/pgsql/database.hxx> +#elif defined(DATABASE_ORACLE) +# include <odb/oracle/database.hxx> +#elif defined(DATABASE_MSSQL) +# include <odb/mssql/database.hxx> +#else +# error unknown database; did you forget to define the DATABASE_* macros? +#endif + +inline std::auto_ptr<odb::database> +create_database (int& argc, char* argv[]) +{ + using namespace std; + using namespace odb::core; + + if (argc > 1 && argv[1] == string ("--help")) + { + cout << "Usage: " << argv[0] << " [options]" << endl + << "Options:" << endl; + +#if defined(DATABASE_MYSQL) + odb::mysql::database::print_usage (cout); +#elif defined(DATABASE_SQLITE) + odb::sqlite::database::print_usage (cout); +#elif defined(DATABASE_PGSQL) + odb::pgsql::database::print_usage (cout); +#elif defined(DATABASE_ORACLE) + odb::oracle::database::print_usage (cout); +#elif defined(DATABASE_MSSQL) + odb::mssql::database::print_usage (cout); +#endif + + exit (0); + } + +#if defined(DATABASE_MYSQL) + auto_ptr<database> db (new odb::mysql::database (argc, argv)); +#elif defined(DATABASE_SQLITE) + auto_ptr<database> db ( + new odb::sqlite::database ( + argc, argv, false, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE)); + + // Create the database schema. Due to bugs in SQLite foreign key + // support for DDL statements, we need to temporarily disable + // foreign keys. + // + { + connection_ptr c (db->connection ()); + + c->execute ("PRAGMA foreign_keys=OFF"); + + transaction t (c->begin ()); + schema_catalog::create_schema (*db); + t.commit (); + + c->execute ("PRAGMA foreign_keys=ON"); + } +#elif defined(DATABASE_PGSQL) + auto_ptr<database> db (new odb::pgsql::database (argc, argv)); +#elif defined(DATABASE_ORACLE) + auto_ptr<database> db (new odb::oracle::database (argc, argv)); +#elif defined(DATABASE_MSSQL) + auto_ptr<database> db (new odb::mssql::database (argc, argv)); +#endif + + return db; +} + +#endif // DATABASE_HXX diff --git a/section/driver.cxx b/section/driver.cxx new file mode 100644 index 0000000..b01454e --- /dev/null +++ b/section/driver.cxx @@ -0,0 +1,133 @@ +// file : section/driver.cxx +// copyright : not copyrighted - public domain + +#include <memory> // std::auto_ptr +#include <iostream> + +#include <odb/database.hxx> +#include <odb/transaction.hxx> + +#include "database.hxx" // create_database + +#include "person.hxx" +#include "person-odb.hxx" + +using namespace std; +using namespace odb::core; + +int +main (int argc, char* argv[]) +{ + try + { + auto_ptr<database> db (create_database (argc, argv)); + + unsigned long id; + + // Create a persistent person object. + // + { + person joe ("Joe", "Dirt"); + joe.bio ("Joe Dirt is a very strange man indeed..."); + joe.nicknames ().push_back ("JD"); + + // At this point the state of a section is undefined since the + // object is transient. + + transaction t (db->begin ()); + id = db->persist (joe); + t.commit (); + + // Now, since the object is persistent, the state of the section + // is loaded and unchanged. + } + + // Load the object and print what we've got. Then update the bio. + // + { + transaction t (db->begin ()); + auto_ptr<person> p (db->load<person> (id)); + + // Now, while the object is loaded, the section is not. If (and + // when) we need to access the section data members, we have to + // load them explicitly. + + cout << p->first () << " " << p->last () << endl; + + db->load (*p, p->extras_section ()); + + // Now the section is loaded and unchanged. + + cout << " " << p->bio () << endl + << " " << p->nicknames ().size () << " nickname(s)" << endl; + + // Update the bio. + // + p->bio ("Joe Dirt is a very clean man indeed..."); + + // Now, the section is marked changed by the bio() modifier. + // Because of that, the following object update will also + // update the section. + // + db->update (*p); + + t.commit (); + } + + // Add a new nickname. + // + { + transaction t (db->begin ()); + + auto_ptr<person> p (db->load<person> (id)); + db->load (*p, p->extras_section ()); + + // Add a new nickname. The nicknames container is now marked + // changed. + // + p->nicknames ().push_back ("Squeaky Clean"); + + // While the section hasn't been marked as changed, a change- + // tracking container that belongs to it has been. As a result, + // the following object update call will automatically mark the + // section as changed and update its state in the database. + // + db->update (*p); + + t.commit (); + } + + // We can also update just the section if we know the rest of + // the object hasn't changed. + // + { + transaction t (db->begin ()); + + auto_ptr<person> p (db->load<person> (id)); + db->load (*p, p->extras_section ()); + + p->nicknames ().push_back ("Dirty Joe"); + db->update (*p, p->extras_section ()); + + t.commit (); + } + + // Load and print the updated object. + // + { + transaction t (db->begin ()); + auto_ptr<person> p (db->load<person> (id)); + db->load (*p, p->extras_section ()); + t.commit (); + + cout << p->first () << " " << p->last () << endl + << " " << p->bio () << endl + << " " << p->nicknames ().size () << " nickname(s)" << endl; + } + } + catch (const odb::exception& e) + { + cerr << e.what () << endl; + return 1; + } +} diff --git a/section/makefile b/section/makefile new file mode 100644 index 0000000..abbb9c9 --- /dev/null +++ b/section/makefile @@ -0,0 +1,122 @@ +# file : section/makefile +# copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC +# license : GNU GPL v2; see accompanying LICENSE file + +include $(dir $(lastword $(MAKEFILE_LIST)))../build/bootstrap.make + +cxx_tun := driver.cxx +odb_hdr := person.hxx +cxx_obj := $(addprefix $(out_base)/,$(cxx_tun:.cxx=.o) $(odb_hdr:.hxx=-odb.o)) +cxx_od := $(cxx_obj:.o=.o.d) + +driver := $(out_base)/driver +dist := $(out_base)/.dist +test := $(out_base)/.test +clean := $(out_base)/.clean + +# Import. +# +$(call import,\ + $(scf_root)/import/odb/stub.make,\ + odb: odb,odb-rules: odb_rules) + +$(call import,\ + $(scf_root)/import/libodb/stub.make,\ + l: odb.l,cpp-options: odb.l.cpp-options) + +ifdef db_id +$(call import,\ + $(scf_root)/import/libodb-$(db_id)/stub.make,\ + l: odb_db.l,cpp-options: odb_db.l.cpp-options) +endif + +ifeq ($(odb_db.l.cpp-options),) +odb_db.l.cpp-options := $(out_base)/.unbuildable +endif + +# Build. +# +$(driver): $(cxx_obj) $(odb_db.l) $(odb.l) +$(cxx_obj) $(cxx_od): cpp_options := -I$(out_base) -I$(src_base) -D$(db_macro) +$(cxx_obj) $(cxx_od): $(odb.l.cpp-options) $(odb_db.l.cpp-options) + +genf := $(addprefix $(odb_hdr:.hxx=-odb),.hxx .ixx .cxx) $(odb_hdr:.hxx=.sql) +gen := $(addprefix $(out_base)/,$(genf)) + +$(gen): $(odb) +$(gen): odb := $(odb) +$(gen) $(dist): export odb_options += --generate-schema --table-prefix section_ +$(gen): cpp_options := -I$(src_base) +$(gen): $(odb.l.cpp-options) + +$(gen): odb_options += --database $(db_id) + +$(call include-dep,$(cxx_od),$(cxx_obj),$(gen)) + +# Alias for default target. +# +$(out_base)/: $(driver) + +# Dist +# +name := $(subst /,-,$(subst $(src_root)/,,$(src_base))) + +$(dist): sources := $(cxx_tun) +$(dist): headers := $(odb_hdr) +$(dist): export name := $(name) +$(dist): export odb_header_stem := $(basename $(odb_hdr)) +$(dist): export extra_dist := README $(call vc8projs,$(name)) \ +$(call vc9projs,$(name)) $(call vc10projs,$(name)) $(call vc11projs,$(name)) +$(dist): + $(call dist-data,$(sources) $(headers) README database.hxx) + $(call meta-automake,../template/Makefile.am) + $(call meta-vc8projs,../template/template,$(name)) + $(call meta-vc9projs,../template/template,$(name)) + $(call meta-vc10projs,../template/template,$(name)) + $(call meta-vc11projs,../template/template,$(name)) + +# Test. +# +$(test): header := $(odb_hdr) +$(test): $(driver) + $(call schema) + $(call message,test $<,$< --options-file $(dcf_root)/$(db_id).options) + +# Clean. +# +$(clean): \ + $(driver).o.clean \ + $(addsuffix .cxx.clean,$(cxx_obj)) \ + $(addsuffix .cxx.clean,$(cxx_od)) \ + $(addprefix $(out_base)/,$(odb_hdr:.hxx=-odb.cxx.hxx.clean)) + +# Generated .gitignore. +# +ifeq ($(out_base),$(src_base)) +$(driver): | $(out_base)/.gitignore + +$(out_base)/.gitignore: files := driver $(genf) +$(clean): $(out_base)/.gitignore.clean + +$(call include,$(bld_root)/git/gitignore.make) +endif + +# How to. +# +$(call include,$(bld_root)/dist.make) +$(call include,$(bld_root)/meta/vc8proj.make) +$(call include,$(bld_root)/meta/vc9proj.make) +$(call include,$(bld_root)/meta/vc10proj.make) +$(call include,$(bld_root)/meta/vc11proj.make) +$(call include,$(bld_root)/meta/automake.make) + +$(call include,$(bld_root)/cxx/standard.make) # cxx_standard +ifdef cxx_standard +$(gen): odb_options += --std $(cxx_standard) +$(call include,$(odb_rules)) +endif + +$(call include,$(bld_root)/cxx/cxx-d.make) +$(call include,$(bld_root)/cxx/cxx-o.make) +$(call include,$(bld_root)/cxx/o-e.make) + diff --git a/section/person.hxx b/section/person.hxx new file mode 100644 index 0000000..996fc19 --- /dev/null +++ b/section/person.hxx @@ -0,0 +1,105 @@ +// file : section/person.hxx +// copyright : not copyrighted - public domain + +#ifndef PERSON_HXX +#define PERSON_HXX + +#include <string> + +#include <odb/core.hxx> +#include <odb/vector.hxx> +#include <odb/section.hxx> + +#pragma db object +class person +{ +public: + person (const std::string& first, const std::string& last) + : first_ (first), last_ (last) + { + } + + const std::string& + first () const + { + return first_; + } + + const std::string& + last () const + { + return last_; + } + + // Biography. + // + const std::string& + bio () const + { + return bio_; + } + + void + bio (const std::string& bio) + { + bio_ = bio; + extras_.change (); // Mark the section as changed. + } + + // Nicknames. + // + typedef odb::vector<std::string> names; + + const names& + nicknames () const + { + return nicknames_; + } + + names& + nicknames () + { + // Because we are using a change-tracking container (odb::vector), + // ODB will automatically mark the section as changed if we update + // the nicknames. + // + return nicknames_; + } + + // The extras section accessor and modifier. Notice that they are + // by-reference. + // + const odb::section& + extras_section () const + { + return extras_; + } + + odb::section& + extras_section () + { + return extras_; + } + +private: + friend class odb::access; + + person () {} + + #pragma db id auto + unsigned long id_; + + std::string first_; + std::string last_; + + #pragma db section(extras_) + std::string bio_; + + #pragma db section(extras_) + names nicknames_; + + #pragma db load(lazy) update(change) + odb::section extras_; +}; + +#endif // PERSON_HXX |