glgerma.blogg.se

The server in the preceding scenario, the large negative value Values are returned from the server as strings, and thenĬonverted as required. In the case of the Statement, which uses the text protocol,

Because the large negative value cannot be sensiblyĬonverted to an unsigned value, 0 is returned. Returned from the server that can be interpreted as an With the binary protocol in this case, a binary value is Text protocol, and Prepared Statements use a binary protocol. The difference results from the fact that Statements use a If a Statement and Prepared Statement are created that To illustrate this, consider the case where a column has beenĭefined as type BIGINT. This is because the protocol used toĬommunicate with the server differs depending on whether a Values depending on whether the call is made from a Statement Std::string MySQL_Connection::getSessionVariable(const std::string & varname) void MySQL_Connection::setSessionVariable(const std::string & varname, const std::string & value)Įxecuting the following and fetching the first return value:įetching the value of a column can sometimes return different To get and set MySQL session variables, Connector/C++ supports theįollowing MySQL_Connection methods, which

& optionName, const void * optionValue) whereĬonn->getClientOption("metadataUseInfoSchema", (void *) &isInfoSchemaUsed) Ĭonn->getClientOption("defaultStatementResultType", (void *) &defaultStmtResType) Ĭonn->getClientOption("defaultPreparedStatementResultType", (void *) &defaultPStmtResType) Void Connection::setClientOption(const std::string The connection through the connection property map, or using The connection property can be set either when establishing Splits the stream into chunks appropriate for the server using Sending the data from the stream to the MySQL server, Connector/C++ If setBlob() is used, this problem does notĪrise because setBlob() takes a streaming Requests due to malevolently long strings. Security issues, such as extremely large memory allocation Situation is not handled in Connector/C++, because it could lead to To the connector using setString() exceedsįew bytes reserved in the protocol for control purposes). The error occurs if the length of the string passed TEXT columns, Connector/C++ developers are advised INFORMATION_SCHEMA and will report the type However, INFORMATION_SCHEMA gives no hint PRIVILEGES: select,insert,update,references Mysql> SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='varbin'\G Mysql> CREATE TABLE varbin (a VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_bin) Method uses the metadata and reports, due to theīINARY flag, that the column type name is VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_bin Suppose that you have a column that accepts a character setĪnd a collation in its specification and you specify a binary “ YES” if the column is an auto-increment column,Ĭonnector/C++ may return different metadata for the same column, JDBC documentation, but column 23 is new: The first 22 columns are as described in the Has 23 columns in its result set, rather than the 22 columnsĭefined by JDBC. The DatabaseMetaData::getColumns() method