NAME
odb - object-relational mapping (ORM) compiler for C++
SYNOPSIS
odb [options] file [file...]
DESCRIPTION
Given a set of C++ classes in a header file, odb
generates C++ code that allows you to persist, query, and update objects
of these classes in a relational database (RDBMS). The relational
database that the generated code should target is specified with the
required --database
option (see below).
For an input file in the form name.hxx
(other
file extensions can be used instead of .hxx
),
in the single-database mode (the default), the generated C++ files
by default have the following names:
name-odb.hxx
(header file),
name-odb.ixx
(inline file), and
name-odb.cxx
(source file).
Additionally, if the --generate-schema
option is
specified and the sql
schema format is requested (see
--schema-format
), the name.sql
database schema file is generated. If the separate
schema format is requested, the database creation code is generated
into the separate name-schema.cxx
file.
In the multi-database mode (see the --multi-database
option below), the generated files corresponding to the
common
database have the same names as in the
single-database mode. For other databases, the file names include
the database name:
name-odb-db.hxx
,
name-odb-db.ixx
,
name-odb-db.cxx
,
name-db.sql
, and
name-schema-db.cxx
(where db
is the database name).
OPTIONS
--help
- Print usage information and exit.
--version
- Print version and exit.
-I
dir
- Add
dir
to the beginning of the list of
directories to be searched for included header files.
-D
name
[=def
]
- Define macro
name
with definition
def
. If definition is omitted, define
name
to be 1.
-U
name
- Cancel any previous definitions of macro
name
,
either built-in or provided with the -D
option.
--database
|-d
db
- Generate code for the
db
database. Valid values
are mssql
, mysql
,
oracle
, pgsql
,
sqlite
, and common
(multi-database
mode only).
--multi-database
|-m
type
- Enable multi-database support and specify its type. Valid values for
this option are
static
and
dynamic
.
In the multi-database mode, options that determine the kind (for
example, --schema-format
), names (for example,
--odb-file-suffix
), or content (for example, prologue
and epilogue options) of the output files can be prefixed with the
database name followed by a colon, for example,
mysql:value
. This restricts the value of such an
option to only apply to generated files corresponding to this
database.
--default-database
db
- When static multi-database support is used, specify the database that
should be made the default. When dynamic multi-database support is used,
common
is always made the default database.
--generate-query
|-q
- Generate query support code. Without this support you cannot use views
and can only load objects via their ids.
--generate-prepared
- Generate prepared query execution support code.
--omit-unprepared
- Omit un-prepared (once-off) query execution support code.
--generate-session
|-e
- Generate session support code. With this option session support will
be enabled by default for all the persistent classes except those for
which it was explicitly disabled using the
db session
pragma.
--generate-schema
|-s
- Generate the database schema. The database schema contains SQL
statements that create database tables necessary to store persistent
classes defined in the file being compiled. Note that by applying this
schema, all the existing information stored in such tables will be lost.
Depending on the database being used (--database
option), the schema is generated either as a standalone SQL file or
embedded into the generated C++ code. By default the SQL file is generated
for the MySQL, PostgreSQL, Oracle, and Microsoft SQL Server databases and
the schema is embedded into the C++ code for the SQLite database. Use the
--schema-format
option to alter the default schema
format.
If database schema evolution support is enabled (that is, the object
model version is specified), then this option also triggers the generation
of database schema migration statements, again either as standalong SQL
files or embedded into the generated C++ code. You can suppress the
generation of schema migration statements by specifying the
--suppress-migration
option.
--generate-schema-only
- Generate only the database schema. Note that this option is only valid
when generating schema as a standalone SQL file (see
--schema-format
for details).
--suppress-migration
- Suppress the generation of database schema migration statements.
--suppress-schema-version
- Suppress the generation of schema version table. If you specify this
option then you are also expected to manually specify the database schema
version and migration state at runtime using the
odb::database::schema_version()
function.
--schema-version-table
name
- Specify the alternative schema version table name instead of the
default
schema_version
. If you specify this option
then you are also expected to manually specify the schema version table
name at runtime using the
odb::database::schema_version_table()
function. The
table name can be qualified.
--schema-format
format
- Generate the database schema in the specified format. Pass
sql
as format
to generate the
database schema as a standalone SQL file or pass
embedded
to embed the schema into the generated C++
code. The separate
value is similar to
embedded
except the schema creation code is generated
into a separate C++ file (name-schema.cxx
by default).
This value is primarily useful if you want to place the schema creation
functionality into a separate program or library. Repeat this option to
generate the same database schema in multiple formats.
--omit-drop
- Omit
DROP
statements from the generated database
schema.
--omit-create
- Omit
CREATE
statements from the generated database
schema.
--schema-name
name
- Use
name
as the database schema name. Schema names
are primarily used to distinguish between multiple embedded schemas in the
schema catalog. They are not to be confused with database schemas
(database namespaces) which are specified with the
--schema
option. If this option is not specified, the
empty name, which is the default schema name, is used.
--fkeys-deferrable-mode
m
- Use constraint checking mode
m
in foreign keys
generated for object relationships. Valid values for this option are
not_deferrable
, immediate
, and
deferred
(default). MySQL and SQL Server do not
support deferrable foreign keys and for these databases such keys are
generated commented out. Other foreign keys generated by the ODB compiler
(such as the ones used to support containers and polymorphic hierarchies)
are always generated as not deferrable.
Note also that if you use either not_deferrable
or
immediate
mode, then the order in which you persist,
update, and erase objects within a transaction becomes important.
--default-pointer
ptr
- Use
ptr
as the default pointer for persistent
objects and views. Objects and views that do not have a pointer assigned
with the db pointer
pragma will use this pointer by
default. The value of this option can be '*
' which
denotes the raw pointer and is the default, or qualified name of a smart
pointer class template, for example, std::shared_ptr
.
In the latter case, the ODB compiler constructs the object or view pointer
by adding a single template argument of the object or view type to the
qualified name, for example
std::shared_ptr<object>
. The ODB runtime uses
object and view pointers to return, and, in case of objects, pass and
cache dynamically allocated instances of object and view types.
Except for the raw pointer and the standard smart pointers defined in
the <memory>
header file, you are expected to
include the definition of the default pointer at the beginning of the
generated header file. There are two common ways to achieve this: you can
either include the necessary header in the file being compiled or you can
use the --hxx-prologue
option to add the necessary
#include
directive to the generated code.
--session-type
type
- Use
type
as the alternative session type instead
of the default odb::session
. This option can be used
to specify a custom session implementation to be use by the persistent
classes. Note that you will also need to include the definition of the
custom session type into the generated header file. This is normally
achieved with the --hxx-prologue*
options.
--profile
|-p
name
- Specify a profile that should be used during compilation. A profile is
an options file. The ODB compiler first looks for a database-specific
version with the name constructed by appending the
-
database
.options
suffix to name
, where database
is
the database name as specified with the --database
option. If this file is not found, then the ODB compiler looks for a
database-independant version with the name constructed by appending just
the .options
suffix.
The profile options files are searched for in the same set of
directories as C++ headers included with the #include
<...>
directive (built-in paths plus those specified with
the -I
options). The options file is first searched
for in the directory itself and then in its odb/
subdirectory.
For the format of the options file refer to the
--options-file
option below. You can repeat this
option to specify more than one profile.
--at-once
- Generate code for all the input files as well as for all the files
that they include at once. The result is a single set of source/schema
files that contain all the generated code. If more than one input file is
specified together with this option, then the
--input-name
option must also be specified in order to
provide the base name for the output files. In this case, the directory
part of such a base name is used as the location of the combined file.
This can be important for the #include
directive
resolution.
--schema
schema
- Specify a database schema (database namespace) that should be assigned
to the persistent classes in the file being compiled. Database schemas are
not to be confused with database schema names (schema catalog names) which
are specified with the
--schema-name
option.
--export-symbol
symbol
- Insert
symbol
in places where DLL export/import
control statements (__declspec(dllexport/dllimport)
)
are necessary. See also the --extern-symbol
option
below.
--extern-symbol
symbol
- If
symbol
is defined, insert it in places where a
template instantiation must be declared extern
. This
option is normally used together with --export-symbol
when both multi-database support and queries are enabled.
--std
version
- Specify the C++ standard that should be used during compilation. Valid
values are
c++98
(default), c++11
,
c++14
, c++17
,
c++20
, c++23
, and
c++26
.
--warn-hard-add
- Warn about hard-added data members.
--warn-hard-delete
- Warn about hard-deleted data members and persistent classes.
--warn-hard
- Warn about both hard-added and hard-deleted data members and
persistent classes.
--output-dir
|-o
dir
- Write the generated files to
dir
instead of the
current directory.
--input-name
name
- Use
name
instead of the input file to derive the
names of the generated files. If the --at-once
option
is specified, then the directory part of name
is used
as the location of the combined file. Refer to the
--at-once
option for details.
--changelog
file
- Read/write changelog from/to
file
instead of the
default changelog file. The default changelog file name is derived from
the input file name and it is placed into the same directory as the input
file. Note that the --output-dir
option does not
affect the changelog file location. In other words, by default, the
changelog file is treated as another input rather than output even though
the ODB compiler may modify it. Use the --changelog-in
and --changelog-out
options to specify different input
and output chaneglog files.
--changelog-in
file
- Read changelog from
file
instead of the default
changelog file. If this option is specified, then you must also specify
the output chanegelog file with --changelog-out
.
--changelog-out
file
- Write changelog to
file
instead of the default
changelog file. If this option is specified, then you must also specify
the input chanegelog file with --changelog-in
.
--changelog-dir
dir
- Use
dir
instead of the input file directory as the
changelog file directory. This directory is also added to changelog files
specified with the --changelog
,
--changelog-in
, and --changelog-in
options unless they are absolute paths.
--init-changelog
- Force re-initialization of the changelog even if one exists (all the
existing change history will be lost). This option is primarily useful for
automated testing.
--odb-file-suffix
suffix
- Use
suffix
to construct the names of the generated
C++ files. In the single-database mode the default value for this option
is -odb
. In the multi-database mode it is
-odb
for the files corresponding to the
common
database and -odb-db
(where db
is the database name) for other
databases.
--sql-file-suffix
suffix
- Use
suffix
to construct the name of the generated
schema SQL file. In the single-database mode by default no suffix is used.
In the multi-database mode the default value for this option is
-db
(where db
is the
database name).
--schema-file-suffix
suffix
- Use
suffix
to construct the name of the generated
schema C++ source file. In the single-database mode the default value for
this option is -schema
. In the multi-database mode it
is -schema-db
(where db
is
the database name). See the --schema-format
option for
details.
--changelog-file-suffix
sfx
- Use
sfx
to construct the name of the changelog
file. In the single-database mode by default no suffix is used. In the
multi-database mode the default value for this option is
-db
(where db
is the
database name).
--hxx-suffix
suffix
- Use
suffix
instead of the default
.hxx
to construct the name of the generated C++ header
file.
--ixx-suffix
suffix
- Use
suffix
instead of the default
.ixx
to construct the name of the generated C++ inline
file.
--cxx-suffix
suffix
- Use
suffix
instead of the default
.cxx
to construct the name of the generated C++ source
file.
--sql-suffix
suffix
- Use
suffix
instead of the default
.sql
to construct the name of the generated database
schema file.
--changelog-suffix
suffix
- Use
suffix
instead of the default
.xml
to construct the name of the changelog file.
--hxx-prologue
text
- Insert
text
at the beginning of the generated C++
header file.
--ixx-prologue
text
- Insert
text
at the beginning of the generated C++
inline file.
--cxx-prologue
text
- Insert
text
at the beginning of the generated C++
source file.
--schema-prologue
text
- Insert
text
at the beginning of the generated
schema C++ source file.
--sql-prologue
text
- Insert
text
at the beginning of the generated
database schema file.
--migration-prologue
text
- Insert
text
at the beginning of the generated
database migration file.
--sql-interlude
text
- Insert
text
after all the DROP
and before any CREATE
statements in the generated
database schema file.
--hxx-epilogue
text
- Insert
text
at the end of the generated C++ header
file.
--ixx-epilogue
text
- Insert
text
at the end of the generated C++ inline
file.
--cxx-epilogue
text
- Insert
text
at the end of the generated C++ source
file.
--schema-epilogue
text
- Insert
text
at the end of the generated schema C++
source file.
--sql-epilogue
text
- Insert
text
at the end of the generated database
schema file.
--migration-epilogue
text
- Insert
text
at the end of the generated database
migration file.
--hxx-prologue-file
file
- Insert the content of
file
at the beginning of the
generated C++ header file.
--ixx-prologue-file
file
- Insert the content of
file
at the beginning of the
generated C++ inline file.
--cxx-prologue-file
file
- Insert the content of
file
at the beginning of the
generated C++ source file.
--schema-prologue-file
file
- Insert the content of
file
at the beginning of the
generated schema C++ source file.
--sql-prologue-file
file
- Insert the content of
file
at the beginning of the
generated database schema file.
--migration-prologue-file
f
- Insert the content of file
f
at the beginning of
the generated database migration file.
--sql-interlude-file
file
- Insert the content of
file
after all the
DROP
and before any CREATE
statements in the generated database schema file.
--hxx-epilogue-file
file
- Insert the content of
file
at the end of the
generated C++ header file.
--ixx-epilogue-file
file
- Insert the content of
file
at the end of the
generated C++ inline file.
--cxx-epilogue-file
file
- Insert the content of
file
at the end of the
generated C++ source file.
--schema-epilogue-file
file
- Insert the content of
file
at the end of the
generated schema C++ source file.
--sql-epilogue-file
file
- Insert the content of
file
at the end of the
generated database schema file.
--migration-epilogue-file
f
- Insert the content of file
f
at the end of the
generated database migration file.
--odb-prologue
text
- Compile
text
before the input header file. This
option allows you to add additional declarations, such as custom traits
specializations, to the ODB compilation process.
--odb-prologue-file
file
- Compile
file
contents before the input header
file. Prologue files are compiled after all the prologue text fragments
(--odb-prologue
option).
--odb-epilogue
text
- Compile
text
after the input header file. This
option allows you to add additional declarations, such as custom traits
specializations, to the ODB compilation process.
--odb-epilogue-file
file
- Compile
file
contents after the input header file.
Epilogue files are compiled after all the epilogue text fragments
(--odb-epilogue
option).
--table-prefix
prefix
- Add
prefix
to table names and, for databases that
have global index and/or foreign key names, to those names as well. The
prefix is added to both names that were specified with the db
table
and db index
pragmas and those that
were automatically derived from class and data member names. If you
require a separator, such as an underscore, between the prefix and the
name, then you should include it into the prefix value.
--index-suffix
suffix
- Use
suffix
instead of the default
_i
to construct index names. The suffix is only added
to names that were automatically derived from data member names. If you
require a separator, such as an underscore, between the name and the
suffix, then you should include it into the suffix value.
--fkey-suffix
suffix
- Use
suffix
instead of the default
_fk
to construct foreign key names. If you require a
separator, such as an underscore, between the name and the suffix, then
you should include it into the suffix value.
--sequence-suffix
suffix
- Use
suffix
instead of the default
_seq
to construct sequence names. If you require a
separator, such as an underscore, between the name and the suffix, then
you should include it into the suffix value.
--sql-name-case
case
- Convert all automatically-derived SQL names to upper or lower case.
Valid values for this option are
upper
and
lower
.
--table-regex
regex
- Add
regex
to the list of regular expressions that
is used to transform automatically-derived table names. See the SQL NAME
TRANSFORMATIONS section below for details.
--column-regex
regex
- Add
regex
to the list of regular expressions that
is used to transform automatically-derived column names. See the SQL NAME
TRANSFORMATIONS section below for details.
--index-regex
regex
- Add
regex
to the list of regular expressions that
is used to transform automatically-derived index names. See the SQL NAME
TRANSFORMATIONS section below for details.
--fkey-regex
regex
- Add
regex
to the list of regular expressions that
is used to transform automatically-derived foreign key names. See the SQL
NAME TRANSFORMATIONS section below for details.
--sequence-regex
regex
- Add
regex
to the list of regular expressions that
is used to transform automatically-derived sequence names. See the SQL
NAME TRANSFORMATIONS section below for details.
--statement-regex
regex
- Add
regex
to the list of regular expressions that
is used to transform automatically-derived prepared statement names. See
the SQL NAME TRANSFORMATIONS section below for details.
--sql-name-regex
regex
- Add
regex
to the list of regular expressions that
is used to transform all automatically-derived SQL names. See the SQL NAME
TRANSFORMATIONS section below for details.
--sql-name-regex-trace
- Trace the process of applying regular expressions specified with the
SQL name
--*-regex
options. Use this option to find
out why your regular expressions don't do what you expected them to
do.
--accessor-regex
regex
- Add
regex
to the list of regular expressions used
to transform data member names to function names when searching for a
suitable accessor function. The argument to this option is a Perl-like
regular expression in the form
/pattern/replacement/
. Any
character can be used as a delimiter instead of '/
'
and the delimiter can be escaped inside pattern
and
replacement
with a backslash (\
).
You can specify multiple regular expressions by repeating this option.
All the regular expressions are tried in the order specified and the
first expression that produces a suitable accessor function is used. Each
expression is tried twice: first with the actual member name and then with
the member's public name which is obtained by removing the common
member name decorations, such as leading and trailing underscores, the
m_
prefix, etc. The ODB compiler also includes a
number of built-in expressions for commonly used accessor names, such as
get_foo
, getFoo
,
getfoo
, and just foo
. The built-in
expressions are tried last.
As an example, the following expression transforms data members with
public names in the form foo
to accessor names in the
form GetFoo
:
/(.+)/Get\u$1/
See also the REGEX AND SHELL QUOTING section below.
--accessor-regex-trace
- Trace the process of applying regular expressions specified with the
--accessor-regex
option. Use this option to find out
why your regular expressions don't do what you expected them to do.
--modifier-regex
regex
- Add
regex
to the list of regular expressions used
to transform data member names to function names when searching for a
suitable modifier function. The argument to this option is a Perl-like
regular expression in the form
/pattern/replacement/
. Any
character can be used as a delimiter instead of '/
'
and the delimiter can be escaped inside pattern
and
replacement
with a backslash (\
).
You can specify multiple regular expressions by repeating this option.
All the regular expressions are tried in the order specified and the
first expression that produces a suitable modifier function is used. Each
expression is tried twice: first with the actual member name and then with
the member's public name which is obtained by removing the common
member name decorations, such as leading and trailing underscores, the
m_
prefix, etc. The ODB compiler also includes a
number of built-in expressions for commonly used modifier names, such as
set_foo
, setFoo
,
setfoo
, and just foo
. The built-in
expressions are tried last.
As an example, the following expression transforms data members with
public names in the form foo
to modifier names in the
form SetFoo
:
/(.+)/Set\u$1/
See also the REGEX AND SHELL QUOTING section below.
--modifier-regex-trace
- Trace the process of applying regular expressions specified with the
--modifier-regex
option. Use this option to find out
why your regular expressions don't do what you expected them to do.
--include-with-brackets
- Use angle brackets (<>) instead of quotes ("") in the generated
#include
directives.
--include-prefix
prefix
- Add
prefix
to the generated
#include
directive paths.
--include-regex
regex
- Add
regex
to the list of regular expressions used
to transform generated #include
directive paths. The
argument to this option is a Perl-like regular expression in the form
/pattern/replacement/
. Any
character can be used as a delimiter instead of '/
'
and the delimiter can be escaped inside pattern
and
replacement
with a backslash (\
).
You can specify multiple regular expressions by repeating this option. All
the regular expressions are tried in the order specified and the first
expression that matches is used.
As an example, the following expression transforms include paths in the
form foo/bar-odb.h
to paths in the form
foo/generated/bar-odb.h
:
%foo/(.+)-odb.h%foo/generated/$1-odb.h%
See also the REGEX AND SHELL QUOTING section below.
--include-regex-trace
- Trace the process of applying regular expressions specified with the
--include-regex
option. Use this option to find out
why your regular expressions don't do what you expected them to do.
--guard-prefix
prefix
- Add
prefix
to the generated header inclusion
guards. The prefix is transformed to upper case and characters that are
illegal in a preprocessor macro name are replaced with underscores.
--show-sloc
- Print the number of generated physical source lines of code
(SLOC).
--sloc-limit
num
- Check that the number of generated physical source lines of code
(SLOC) does not exceed
num
.
--options-file
file
- Read additional options from
file
. Each option
should appear on a separate line optionally followed by space or equal
sign (=
) and an option value. Empty lines and lines
starting with #
are ignored. Option values can be
enclosed in double ("
) or single
('
) quotes to preserve leading and trailing
whitespaces as well as to specify empty values. If the value itself
contains trailing or leading quotes, enclose it with an extra pair of
quotes, for example '"x"'
. Non-leading and
non-trailing quotes are interpreted as being part of the option value.
The semantics of providing options in a file is equivalent to providing
the same set of options in the same order on the command line at the point
where the --options-file
option is specified except
that the shell escaping and quoting is not required. Repeat this option to
specify more than one options file.
-x
option
- Pass
option
to the underlying C++ compiler
(g++
). The option
value that
doesn't start with '-
' is considered the
g++
executable name.
-v
- Print the commands executed to run the stages of compilation.
--trace
- Trace the compilation process.
--mysql-engine
engine
- Use
engine
instead of the default
InnoDB
in the generated database schema file. For more
information on the storage engine options see the MySQL documentation. If
you would like to use the database-default engine, pass
default
as the value for this option.
--sqlite-override-null
- Make all columns in the generated database schema allow
NULL
values. This is primarily useful in schema
migration since SQLite does not support dropping of columns. By making all
columns NULL
we can later "delete" them by setting
their values to NULL
. Note that this option overrides
even the not_null
pragma.
--sqlite-lax-auto-id
- Do not force monotonically increasing automatically-assigned object
ids. In this mode the generated database schema omits the
AUTOINCREMENT
keyword which results in faster object
persistence but may lead to automatically-assigned ids not being in a
strictly ascending order. Refer to the SQLite documentation for
details.
--pgsql-server-version
ver
- Specify the minimum PostgreSQL server version with which the generated
C++ code and schema will be used. This information is used to enable
version-specific optimizations and workarounds in the generated C++ code
and schema. The version must be in the
major.minor
form, for example,
9.1
. If this option is not specified, then
7.4
or later is assumed.
--oracle-client-version
ver
- Specify the minimum Oracle client library (OCI) version with which the
generated C++ code will be linked. This information is used to enable
version-specific optimizations and workarounds in the generated C++ code.
The version must be in the
major.minor
form, for example, 11.2
. If this option is not
specified, then 10.1
or later is assumed.
--oracle-warn-truncation
- Warn about SQL names that are longer than 30 characters and are
therefore truncated. Note that during database schema generation
(
--generate-schema
) ODB detects when such truncations
lead to name conflicts and issues diagnostics even without this option
specified.
--mssql-server-version
ver
- Specify the minimum SQL Server server version with which the generated
C++ code and schema will be used. This information is used to enable
version-specific optimizations and workarounds in the generated C++ code
and schema. The version must be in the
major.minor
form, for example,
9.0
(SQL Server 2005), 10.5
(2008R2), or 11.0
(2012). If this option is not
specified, then 10.0
(SQL Server 2008) or later is
assumed.
--mssql-short-limit
size
- Specify the short data size limit. If a character, national character,
or binary data type has a maximum length (in bytes) less than or equal to
this limit, then it is treated as short data, otherwise it is
long data. For short data ODB pre-allocates an intermediate buffer
of the maximum size and binds it directly to a parameter or result column.
This way the underlying API (ODBC) can read/write directly from/to this
buffer. In the case of long data, the data is read/written in chunks using
the
SQLGetData()
/SQLPutData()
ODBC
functions. While the long data approach reduces the amount of memory used
by the application, it may require greater CPU resources. The default
short data limit is 1024 bytes. When setting a custom short data limit,
make sure that it is sufficiently large so that no object id in the
application is treated as long data.
SQL NAME TRANSFORMATIONS
The ODB compiler provides a number of mechanisms for transforming
automatically-derived SQL names, such as tables, columns, etc.,
to match a specific naming convention. At the higher level, we can
add a prefix to global names (tables and, for some databases,
indexes and/or foreign keys) with the --table-prefix
option. Similarly, we can specify custom suffixes for
automatically-derived
index (--index-suffix
; default is _i
),
foreign key (--fkey-suffix
; default is _fk
), and
sequence (--sequence-suffix
; default is _seq
)
names. Finally, we can also convert all the names to upper or lower
case with the --sql-name-case
option (valid values
are upper
and lower
).
At the lower level we can specify a set of regular expressions to
implement arbitrary transformations of the automatically-derived SQL
names. If we want a particular regular expression only to apply to
a specific name, for example, table or column, then we use one of the
--kind-regex
options, where
kind
can be table
,
column
, index
,
fkey
, sequence
, or
statement
. On the other hand, if we want our
regular expressions to apply to all SQL names, then we use the
--sql-name-regex
option.
The interaction between the higher and lower level transformations
is as follows. Prefixes and suffixes are added first. Then the
regular expression transformations are applied. Finally, if requested,
the name is converted to upper or lower case. Note also that all of
these transformations except for --table-prefix
only apply to automatically-derived names. In other words, if a table,
column, etc., name was explicitly specified with a pragma, then it
is used as is, without applying any (except for the table prefix)
transformations.
The value for the --*-regex
options is a Perl-like
regular expression in the form
/pattern/replacement/
.
Any character can be used as a delimiter instead of /
and the delimiter can be escaped inside pattern
and
replacement
with a backslash (\
).
You can also specify multiple regular expressions by repeating these
options.
All the regular expressions are tried in the order specified with the
name-specific expressions (for example, --table-regex
)
tried first followed by the generic expressions
(--sql-name-regex
). The first expression that
matches is used.
As an example, consider a regular expression that transforms a class
name in the form CFoo
to a table name in the
form FOO
:
--table-regex '/C(.+)/\U$1/'
As a more interesting example, consider the transformation of class
names that follow the upper camel case convention (for example,
FooBar
) to table names that follow the
underscore-separated, all upper case convention (for example,
FOO_BAR
). For this case we have to use
separate expressions to handle one-word, two-word, etc.,
names:
--table-regex '/([A-z][a-z]+)/\U$1/'
--table-regex '/([A-z][a-z]+)([A-z][a-z]+)/\U$1_$2/'
See also the REGEX AND SHELL QUOTING section below.
REGEX AND SHELL QUOTING
When entering a regular expression argument in the shell
command line it is often necessary to use quoting (enclosing
the argument in " "
or
' '
) in order to prevent the shell
from interpreting certain characters, for example, spaces as
argument separators and $
as variable
expansions.
Unfortunately it is hard to achieve this in a manner that is
portable across POSIX shells, such as those found on
GNU/Linux and UNIX, and Windows shell. For example, if you
use " "
for quoting you will get a
wrong result with POSIX shells if your expression contains
$
. The standard way of dealing with this
on POSIX systems is to use ' '
instead.
Unfortunately, Windows shell does not remove ' '
from arguments when they are passed to applications. As a result you
may have to use ' '
for POSIX and
" "
for Windows ($
is
not treated as a special character on Windows).
Alternatively, you can save regular expression options into
a file, one option per line, and use this file with the
--options-file
option. With this approach
you don't need to worry about shell quoting.
DIAGNOSTICS
If the input file is not valid C++, odb
will issue diagnostic messages to STDERR and exit with non-zero exit
code.
BUGS
Send bug reports to the
odb-users@codesynthesis.com mailing list.