diff options
Diffstat (limited to 'mapping')
-rw-r--r-- | mapping/README | 65 | ||||
-rw-r--r-- | mapping/makefile | 6 |
2 files changed, 69 insertions, 2 deletions
diff --git a/mapping/README b/mapping/README new file mode 100644 index 0000000..fffadcb --- /dev/null +++ b/mapping/README @@ -0,0 +1,65 @@ +This examples shows how to customize the mapping between C++ value types +and database types. The example changes the default mapping for the 'bool' +type which is now stored in the database as the "true" or "false" string. +It also maps the user-defined 'date' type to a suitable database date type. + +The example consists of the following files: + +person.hxx + Header file defining the 'date' value type and the 'person' persistent + class. It also uses the ODB value type pragma to map 'bool' to the + 'VARCHAR(5)' database type and 'date' to the 'DATE' database type. + +traits.hxx + ODB 'value_traits' template specializations for the 'bool' and 'date' + types. These specializations implement conversion between these types + and their database counterparts. + +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-query --generate-schema \ + --hxx-prologue '#include "traits.hxx"' person.hxx + + Where <database> stands for the database system we are using, for example, + 'mysql'. + + The --hxx-prologue option included the traits.hxx header at the beginning + of the generated person-odb.hxx file. This makes the 'value_traits' + specializations defined in traits.hxx known to the generated database + support code. + +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 'person' class and the database support + code for this class. 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 number of 'person' objects in the database + and executes a query to find objects matching certain criteria. + +To run the example we first need to create the database schema. 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/mapping/makefile b/mapping/makefile index 7b9c72e..79f79d8 100644 --- a/mapping/makefile +++ b/mapping/makefile @@ -71,9 +71,11 @@ $(dist): headers := $(odb_hdr) $(dist): export name := $(name) $(dist): export extra_headers := traits.hxx $(dist): export odb_header_stem := $(basename $(odb_hdr)) -$(dist): export extra_dist := $(call vc9projs,$(name)) $(call vc10projs,$(name)) +$(dist): export extra_dist := README $(call vc9projs,$(name)) \ +$(call vc10projs,$(name)) $(dist): - $(call dist-data,$(sources) $(headers) $(extra_headers) database.hxx) + $(call dist-data,$(sources) $(headers) $(extra_headers) \ +README database.hxx) $(call meta-automake,../template/Makefile.am) $(call meta-vc9projs,../template/template,$(name)) $(call meta-vc10projs,../template/template,$(name)) |