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0001 # MySQL Backend Reference 0002 0003 SOCI backend for accessing MySQL database. 0004 0005 ## Prerequisites 0006 0007 ### Supported Versions 0008 0009 The SOCI MySQL backend should in principle work with every version of MySQL 5.x. 0010 Some of the features (transactions, stored functions) are not available when MySQL server doesn't support them. 0011 0012 ### Tested Platforms 0013 0014 |MySQL|OS|Compiler| 0015 |--- |--- |--- | 0016 |8.0.1|Windows 10|Visual Studio 2017 (15.3.3)| 0017 |5.5.28|OS X 10.8.2|Apple LLVM version 4.2 (clang-425.0.24)| 0018 |5.0.96|Ubuntu 8.04.4 LTS (Hardy Heron)|g++ (GCC) 4.2.4 (Ubuntu 4.2.4-1ubuntu4)| 0019 |5.7.22|macOS High Sierra 10.13.5|AppleClang 9.1.0.9020039| 0020 0021 ### Required Client Libraries 0022 0023 The SOCI MySQL backend requires MySQL's `libmysqlclient` client library from the [MySQL Connector/C](https://dev.mysql.com/downloads/connector/c/). 0024 0025 Note that the SOCI library itself depends also on `libdl`, so the minimum set of libraries needed to compile a basic client program is: 0026 0027 -lsoci_core -lsoci_mysql -ldl -lmysqlclient 0028 0029 ## Connecting to the Database 0030 0031 To establish a connection to a MySQL server, create a `session` object using the `mysql` backend factory together with a connection string: 0032 0033 session sql(mysql, "db=test user=root password='Ala ma kota'"); 0034 0035 // or: 0036 session sql("mysql", "db=test user=root password='Ala ma kota'"); 0037 0038 // or: 0039 session sql("mysql://db=test user=root password='Ala ma kota'"); 0040 0041 The set of parameters used in the connection string for MySQL is: 0042 0043 * `dbname` or `db` or `service` (required) 0044 * `user` 0045 * `password` or `pass` 0046 * `host` 0047 * `port` 0048 * `unix_socket` 0049 * `sslca` 0050 * `sslcert` 0051 * `local_infile` - should be `0` or `1`, `1` means `MYSQL_OPT_LOCAL_INFILE` will be set. 0052 * `charset` 0053 * `reconnect` - if set to 1, set `MYSQL_OPT_RECONNECT` to reconnect on connection loss. 0054 * `connect_timeout` - should be positive integer value that means seconds corresponding to `MYSQL_OPT_CONNECT_TIMEOUT`. 0055 * `read_timeout` - should be positive integer value that means seconds corresponding to `MYSQL_OPT_READ_TIMEOUT`. 0056 * `write_timeout` - should be positive integer value that means seconds corresponding to `MYSQL_OPT_WRITE_TIMEOUT`. 0057 0058 Once you have created a `session` object as shown above, you can use it to access the database, for example: 0059 0060 int count; 0061 sql << "select count(*) from invoices", into(count); 0062 0063 (See the [connection](../connections.md) and [data binding](../binding.md) documentation 0064 for general information on using the `session` class.) 0065 0066 ## SOCI Feature Support 0067 0068 ### Dynamic Binding 0069 0070 The MySQL backend supports the use of the SOCI `row` class, which facilitates retrieval of data which type is not known at compile time. 0071 0072 When calling `row::get<T>()`, the type you should pass as `T` depends upon the underlying database type. 0073 For the MySQL backend, this type mapping is: 0074 0075 |MySQL Data Type|SOCI Data Type|`row::get<T>` specializations| 0076 |--- |--- |--- | 0077 |FLOAT, DOUBLE, DECIMAL and synonyms|dt_double|double| 0078 |TINYINT, TINYINT UNSIGNED, SMALLINT, SMALLINT UNSIGNED, INT|dt_integer|int| 0079 |INT UNSIGNED|dt_long_long|long long or unsigned| 0080 |BIGINT|dt_long_long|long long| 0081 |BIGINT UNSIGNED|dt_unsigned_long_long|unsigned long long| 0082 |CHAR, VARCHAR, BINARY, VARBINARY, TINYBLOB, MEDIUMBLOB, BLOB,LONGBLOB, TINYTEXT, MEDIUMTEXT, TEXT, LONGTEXT, ENUM|dt_string|std::string| 0083 |TIMESTAMP (works only with MySQL >= 5.0), DATE, TIME, DATETIME|dt_date|std::tm| 0084 0085 (See the [dynamic resultset binding](../types.md#dynamic-binding) documentation for general information 0086 on using the `Row` class.) 0087 0088 ### Binding by Name 0089 0090 In addition to [binding by position](../binding.md#binding-by-position), the MySQL backend supports 0091 [binding by name](../binding.md#binding-by-name), via an overload of the `use()` function: 0092 0093 int id = 7; 0094 sql << "select name from person where id = :id", use(id, "id") 0095 0096 It should be noted that parameter binding of any kind is supported only by means of emulation, since the underlying API used by the backend doesn't provide this feature. 0097 0098 ### Bulk Operations 0099 0100 ### Transactions 0101 0102 [Transactions](../transactions.md) are also supported by the MySQL backend. Please note, however, that transactions can only be used when the MySQL server supports them (it depends on options used during the compilation of the server; typically, but not always, servers >=4.0 support transactions and earlier versions do not) and only with appropriate table types. 0103 0104 ### BLOB Data Type 0105 0106 SOCI `blob` interface is not supported by the MySQL backend. 0107 0108 Note that this does not mean you cannot use MySQL's `BLOB` types. They can be selected using the usual SQL syntax and read into `std::string` on the C++ side, so no special interface is required. 0109 0110 ### RowID Data Type 0111 0112 The `rowid` functionality is not supported by the MySQL backend. 0113 0114 ### Nested Statements 0115 0116 Nested statements are not supported by the MySQL backend. 0117 0118 ### Stored Procedures 0119 0120 MySQL version 5.0 and later supports two kinds of stored routines: stored procedures and stored functions (for details, please consult the [Defining Stored Programs](https://dev.mysql.com/doc/refman/5.5/en/stored-programs-defining.html)). Stored functions can be executed by using SOCI's [procedure class](../procedures.md). There is currently no support for stored procedures. 0121 0122 ## Native API Access 0123 0124 SOCI provides access to underlying datbabase APIs via several `get_backend()` functions, as described in the [Beyond SOCI](../beyond.md) documentation. 0125 0126 The MySQL backend provides the following concrete classes for native API access: 0127 0128 |Accessor Function|Concrete Class| 0129 |--- |--- | 0130 |session_backend * session::get_backend()|mysql_session_backend| 0131 |statement_backend * statement::get_backend()|mysql_statement_backend| 0132 0133 ## Backend-specific extensions 0134 0135 None. 0136 0137 ## Configuration options 0138 0139 None.