SQLite3 Backend Reference
SOCI backend for accessing SQLite 3 database.
Prerequisites
Supported Versions
The SOCI SQLite3 backend is supported for use with SQLite3 >= 3.1
Tested Platforms
| SQLite3 | OS | Compiler |
|---|---|---|
| 3.12.1 | Windows Server 2016 | MSVC++ 14.1 |
| 3.12.1 | Windows Server 2012 R2 | MSVC++ 14.0 |
| 3.12.1 | Windows Server 2012 R2 | MSVC++ 12.0 |
| 3.12.1 | Windows Server 2012 R2 | MSVC++ 11.0 |
| 3.12.1 | Windows Server 2012 R2 | Mingw-w64/GCC 4.8 |
| 3.7.9 | Ubuntu 12.04 | g++ 4.6.3 |
| 3.4.0 | Windows XP | (cygwin) g++ 3.4.4 |
| 3.4.0 | Windows XP | Visual C++ 2005 Express Edition |
| 3.3.8 | Windows XP | Visual C++ 2005 Professional |
| 3.5.2 | Mac OS X 10.5 | g++ 4.0.1 |
| 3.3.4 | Ubuntu 5.1 | g++ 4.0.2 |
| 3.3.4 | Windows XP | (cygwin) g++ 3.3.4 |
| 3.3.4 | Windows XP | Visual C++ 2005 Express Edition |
| 3.2.1 | Linux i686 2.6.10-gentoo-r6 | g++ 3.4.5 |
| 3.1.3 | Mac OS X 10.4 | g++ 4.0.1 |
| 3.24.0 | macOS High Sierra 10.13.5 | AppleClang 9.1.0.9020039 |
Required Client Libraries
The SOCI SQLite3 backend requires SQLite3's libsqlite3 client library.
Connecting to the Database
To establish a connection to the SQLite3 database, create a Session object using the SQLite3 backend factory together with the database file name:
session sql(sqlite3, "database_filename");
// or:
session sql("sqlite3", "db=db.sqlite timeout=2 shared_cache=true");
The set of parameters used in the connection string for SQLite is:
dbnameordbtimeout- set sqlite busy timeout (in seconds) (link)readonly- open database in read-only mode instead of the default read-write (note that the database file must already exist in this case, see the documentation)synchronous- set the pragma synchronous flag (link)shared_cache- should betrue(link)vfs- set the SQLite VFS used to as OS interface. The VFS should be registered before opening the connection, see the documenation
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);
(See the connection and data binding documentation for general information on using the session class.)
SOCI Feature Support
Dynamic Binding
The SQLite3 backend supports the use of the SOCI row class, which facilitates retrieval of data whose type is not known at compile time.
When calling row::get<T>(), the type you should pass as T depends upon the underlying database type.
For the SQLite3 backend, this type mapping is complicated by the fact the SQLite3 does not enforce [types][INTEGER_PRIMARY_KEY] and makes no attempt to validate the type names used in table creation or alteration statements. SQLite3 will return the type as a string, SOCI will recognize the following strings and match them the corresponding SOCI types:
| SQLite3 Data Type | SOCI Data Type | row::get<T> specializations |
|---|---|---|
| float, double | dt_double | double |
| int8, bigint | dt_long_long | long long |
| unsigned big int | dt_unsigned_long_long | unsigned long long |
| int, boolean | dt_integer | int |
| text, char* | dt_string | std::string |
| date, time | dt_date | std::tm |
[INTEGER_PRIMARY_KEY] : There is one case where SQLite3 enforces type. If a column is declared as "integer primary key", then SQLite3 uses that as an alias to the internal ROWID column that exists for every table. Only integers are allowed in this column.
(See the dynamic resultset binding documentation for general information on using the row class.)
Binding by Name
In addition to binding by position, the SQLite3 backend supports binding by name, via an overload of the use() function:
int id = 7;
sql << "select name from person where id = :id", use(id, "id")
The backend also supports the SQLite3 native numbered syntax, "one or more literals can be replace by a parameter "?" or ":AAA" or "@AAA" or "$VVV" where AAA is an alphanumeric identifier and VVV is a variable name according to the syntax rules of the TCL programming language." [1]:
int i = 7;
int j = 8;
sql << "insert into t(x, y) values(?, ?)", use(i), use(j);
Bulk Operations
The SQLite3 backend has full support for SOCI's bulk operations interface. However, this support is emulated and is not native.
Transactions
Transactions are also fully supported by the SQLite3 backend.
BLOB Data Type
The SQLite3 backend supports working with data stored in columns of type Blob, via SOCI's BLOB class. Because of SQLite3 general typelessness the column does not have to be declared any particular type.
RowID Data Type
In SQLite3 RowID is an integer. "Each entry in an SQLite table has a unique integer key called the "rowid". The rowid is always available as an undeclared column named ROWID, OID, or ROWID. If the table has a column of type INTEGER PRIMARY KEY then that column is another an alias for the rowid."[2]
Nested Statements
Nested statements are not supported by SQLite3 backend.
Stored Procedures
Stored procedures are not supported by SQLite3 backend
Native API Access
SOCI provides access to underlying datbabase APIs via several get_backend() functions, as described in the beyond SOCI documentation.
The SQLite3 backend provides the following concrete classes for navite API access:
| Accessor Function | Concrete Class |
|---|---|
| session_backend* session::get_backend() | sqlie3_session_backend |
| statement_backend* statement::get_backend() | sqlite3_statement_backend |
| rowid_backend* rowid::get_backend() | sqlite3_rowid_backend |
Backend-specific extensions
SQLite3 result code support
SQLite3 result code is provided via the backend specific sqlite3_soci_error class. Catching the backend specific error yields the value of SQLite3 result code via the result() method.
Configuration options
None