编程实践CAPIs包含在mysqlclient库文件当中与MySQL

MySQL_C_API编程实践-writtenby1MySQLC CAPIs包含在mysq库文件当中，与MySQL的源代码一块，用于连接到数据int{ ret= t,if(mysql_library_init(0,NULL,NULL))fprintf(stderr,"couldnotinitializeMySQLlibrary\n");}MYSQL*mysql_real_connect(MYSQL*mysql,constchar*host,constchar*user,constchar*passwd,constchar*db,unsignedintport,constchar*unix_socket,unsignedlong_flag)unsignedintmysql_errno(MYSQL*mysql);constchar*mysql_error(MYSQL*mysql);connect=mysql_real_connect(&mysql,"localhost","root","123456","mydb2",0,NULL,0);if(connect==NULL){ret=printf("funcmysql_real_connect()err\n");returnret;}{printf(" }printf("connect:%d&mysql:%d\n",connect,&mysql);}MySQLmysq的开发头文 为/usr/include/mysqlmysqgcc- dm01_o o.c-I/usr/include/mysql-L/usr/lib64/mysql .o):Infunction .c:(.text+0x31):undefinedreferenceto.c:(.text+0x4f):undefinedreferenceto//libmysql _globallookupundefinedreferencetodm01_o.c:49:警告：初始化将指针赋给整数，未作类型转 ref. ality_v0]+0x0):undefinedreferenceto` - - - - - undefinedreferencesto`floor'followdm01_o.c:70:警告：初始化将指针赋给整数，未作类型转//导致没有 .a(net_serv.cc.o):(.data.DW.ref.gxx_ ref.gxx_ ality_v0]+0x0):undefinedreferenceto`gxx_ MySQLGCCgcc- dm01_o o.c-I/usr/include/mysql-L/usr/lib64/mysql--ldl-lpthread-lm- -MySQLmakefileLFLAGS=-L/usr/lib64/mysql-lmysql-ldl-lpthread-lm-lrt-BIN=dm01_odm02_query$(CC) -c - $(CC)$(CFLAGS) $(LFLAGS)- $(CC)$(CFLAGS) $(LFLAGS)- rm-f*.o2MySQLCAPIMYSQLCAPI1MYSQL1MYSQL 通过调用mysql_library_init(),MYSQL 通过调用mysql_init()mysql_real_connect()连接 SQL 通过调用mysql_close()MYSQL 通过调用mysql_library_end()MYSQL初始化接句柄结#includeMYSQL*mysql_init(MYSQLMYSQL*mysql_real_connect(MYSQL*connection,constchar*server_host,constchar*sql_user_name,constchar*sql_password,constchar*db_name,unsignedintport_number,constchar*unix_socket_name,unsignedintIntmysql_options(MYSQLoption_to_set,constcharunsignedintmysql_errno(MYSQLmysqlAPI函数的错误代码，该函数调用可SQLintmysql_query(MYSQL*mysql,constchar1SQL语句，而且不应为语句添加终结分号或”\g”mysql_real_query返回上次语句所涉及到记录的行对于成功检索了数据的每个查询，必须调用mysql_store_result()该函数将查询的全部结果到客户端，分配1个MYSQL_RES结构，并将 mit(MYSQL*mysql,my_bool函数说明如果模式为 启动 mit模式；如果模式为0，mit模式 mit(MYSQL 不像mysql_store_result()那样把结果集实际到客户端。它必须通过CAPI开连接时，必须将标志参数中的_MULTI_STATEMENTS选项指定给 。也可以通过调用api如果mysql指向的连接句柄。MYSQL*mysql_real_connect(MYSQL*mysql,constchar*host,constchar*user,constchar*passwd,constchar*db,unsignedintport,constchar*unix_socket,unsignedlong函数功能:MySQLconnect=mysql_real_connect(&mysql,"localhost","root","123456","mydb2",0,0intmysql_query(MYSQL*mysql,constcharintmysql_real_query(MYSQL*mysql,constchar*query,unsignedlongmysql_store_result()将查询的全部结果到客户端，分配1个MYSQL_RES结构，取结果集中的行，或调用mysql_row_seek()和mysql_row_l()来获取或设置结果集一旦完成了对结果集的操作，必须调用 MYSQL_RES*mysql_use_result(MYSQL*mysql)不像mysql_store_result()那样把结果集实际到客户端。它必须通过1MySQL服务器，这需要使用mysql库，MySQL的大多数客户端API（除了3MySQL的函数）中都会用到。MYSQL*mysql_init(MYSQL*mysql)constchar*user,constchar*passwd,constchar*db,unsignedintport,const*unix_socket,unsignedlong也可另式来进行连接。先用MYSQL_READ_DEFAULT_FILE作为选项名来调mysql_options(),再调用mysql_real_connect()来连接服务器;mysql_options(*mysql,MYSQL_READ_DEFAULT_FILE," mysql_real_connect(*mysql,NULL,NULL,NULL,NULL,0,NULL,0) f文件中记录了连接MySQL服务器所需的各项参数（地址，端口，用户名，密码，数据库，字符集，UnixSocket等。这样可以灵活的修改连接参数而不必重新编译voidmysql_close(MYSQL*mysql)4intmysql_query(MYSQL*mysql,constchar2）UPDATE,DELETEINSERTmysql_affected_rows()获知受影响的记录数。my_ulonglongmysql_affected_rows(MYSQL*mysql)。mysql_insert_idUPDATEINSERTmy_ulonglongmysql_insert_id(MYSQL3-1）式是通过mysql_store_result()将整个结果集全部取回来。MYSQL_RES*mysql_store_result(MYSQL*mysql)3-2）另式则是调用mysql_use_result()初始化获取操作，但暂时不取回任何记录。MYSQL_RES*mysql_use_result(MYSQL*mysql)；3-3两种方法均通过mysql_fetch_row()来每一条记录MYSQL_ROWmysql_fetch_row(MYSQL_RES注意：若先前调用的是mysql_store_result(),则直接在本地记录；若先前调用mysql_use_result(),则此时才到服务器上去获取记录。4）当处理完结果集后，调用mysql__result()来释放它所占的内存。voidmysql__result(MYSQL_RES*result)。unsignedintmysql_errno(MYSQL*mysql)constchar*mysql_error(MYSQL*mysql)5.(PreparedMySQLCAPI还提供了另式来执行SQL语句，即先预处理(prepare)再执(execute).SQLMYSQL_STMT*mysql_stmt_init(MYSQL*mysql)intmysql_stmt_prepare(MYSQL_STMT*stmt,constchar*stmt_str,unsignedlongmy_boolmysql_stmt_bind_param(MYSQL_STMT*stmt,MYSQL_BIND*bind)TEXTBLOB, parameter_number,constchar*data,unsignedlonglength)intmysql_stmt_execute(MYSQL_STMTmy_ulonglongmysql_stmt_insert_id(MYSQL_STMT*stmt)来获得被改变的记录数和生my_ulonglongmysql_stmt_affected_rows(MYSQL_STMT*stmt)my_ulonglongmysql_stmt_insert_id(MYSQL_STMT*stmt)mysql_stmt_bind_result()对结果集中的字段进行绑定。my_boolmysql_stmt_bind_result(MYSQL_STMT*stmt,MYSQL_BIND*bind)intmysql_stmt_fetch(MYSQL_STMT*stmt)intmysql_stmt_store_result(MYSQL_STMT3-6,my_boolmysql_stmt_close(MYSQL_STMT*)APIunsignedintmysql_stmt_errno(MYSQL_STMT*stmt)constchar*mysql_stmt_error(MYSQL_STMT*stmt) MYSQLCAPI2.2节，调用思路分析：5预处理语句(Prepared1.mysql_stmt_init()创建预处理语句句柄。要想在服务器上准备预处理语句，mysql_stmt_prepare(SQL2.mysql_stmt_result_metadata()以获得结果集元 如果语句生成了结果集，数据缓冲，通过调 CAPI开连接时，必须将标志参数中的_MULTI_STATEMENTS选项指定给 。也可以通过调用/*Connecttoserverwithoption mysql_real_connect(...,_MULTI_STATEMENTS);/*NowexecutemultiplequeriesINSERTINTOtest_tableUPDATEtest_tableSETid=20WHEREid=10;\SELECT*FROMtest_table;\{/*Processallresultsprintf("totalaffectedrows:%lld",if(!(result={printf(stderr,"Gotfatalerrorprocessingquery\n");}process_result_set(result);/*function*/}whileMYSQL_TIME结构TIMESAMPCint{ret=0,status= mysqlmysql=mysql_real_connect(mysql,"localhost","root","123456","mydb2",0,NULL,_MULTI_STATEMENTS);if(mysql=={ret=printf("%s",printf("funcmysql_real_connect()err:%d\n",ret);returnret;}{printf(" } //////createtabletest_table(date_fielddate, time_fieldtime, timestamp);charquery[1024]="INSERTINTOtest_table(date_field,time_field,timestamp_field)if(!stmt){fprintf(stderr,"mysql_stmt_init(),outofmemory\n");}{fprintf(stderr,"\n%s",mysql_stmt_error(stmt));}/*setupinputbuffersforall3parameters*/bind[0].buffer_type=MYSQL_TYPE_DATE;bind[0].buffer=(char*)&ts;bind[0].is_null=bind[0].length=bind[1]=bind[2]=/*supplythedatatobesentinthetsstructure*/ts.year=2002;ts.month=ts.day=ts.hour=ts.minute=ts.second=//Closethestatementif{fprintf(stderr,"failedwhileclosingthestatement\n");fprintf(stderr,"%s\n",mysql_stmt_error(stmt));}}2.5MYSQL默认是自动提交的，也就是你提交一个QUERY，它就直接执行！我们可以通过 mit=1mysqlINNODBMYISAM#define #define #defineUNSET_TRAN #defineCOMMIT_TRAN #define {intret=ret=mysql_query(mysql,BEGIN_TRAN);if(ret!=0){printf("funcmysql_query()err:%d\n",ret);returnret;}ret=mysql_query(mysql,SET_TRAN);if(ret!=0){printf("funcmysql_query()err:%d\n",ret);returnret;}return}{intret=ret=mysql_query(mysql,ROLLBACK_TRAN);if(ret!=0){printf("funcmysql_query()err:%d\n",ret);returnret;}ret=mysql_query(mysql,if(ret!={printf("funcmysql_query()err:%d\n",ret);returnret;}return} mit(MYSQL{intret=ret=mysql_query(mysql,COMMIT_TRAN);if(ret!=0){printf("funcmysql_query()err:%d\n",ret);returnret;}ret=mysql_query(mysql,UNSET_TRAN);if(ret!=0){printf("funcmysql_query()err:%d\n",ret);returnret;}return}#definesql01"INSERTINTOtest_table(col1,col2,col3)VALUES(10,'10','1')"#definesql02"INSERTINTOtest_table(col1,col2,col3)VALUES(20,'20','2')"#definesql03"INSERTINTOtest_table(col1,col2,col3)VALUES(30