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POHow can I verify if database is set
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I called <code>mysql_select_db()</code> and it returned no errors, but when I called <code>mysql_query()</code> I got the following error: <blockquote> No database selected. </blockquote> I found a parameter of MYSQL struct. It is some char* calls db. What does it represent? <code>mysql_select_db()</code> does changes this parameter? Thanks. Edit: My main(): <pre><code>#include t-mysql.h ... T_MYSQL *db = (T_MYSQL*) malloc(sizeof(T_MYSQL)); strcpy(db->database_name,mysql_database_name); strcpy(db->password,mysql_password); strcpy(db->root_password,mysql_root_password); strcpy(db->server,mysql_server); strcpy(db->table_name,mysql_table_name); strcpy(db->user,mysql_user); strcpy(db->query_create_db,query_create_db); strcpy(db->query_create_table,query_create_table); t_mysql_init(db); t_mysql_connect(db); t_mysql_createdb(db); t_mysql_setdb(db); t_mysql_createtable(db); ... </code></pre> t-mysql.h: <pre><code>#include <stdio.h> #include <mysql.h> #include <my_global.h> #ifndef T_MYSQL_H_ #define T_MYSQL_H_ #define MAX_NAME_LENGTH 128 #define MAX_QUERY_LENGTH 1024 typedef struct { MYSQL *con; char password[MAX_NAME_LENGTH]; char root_password[MAX_NAME_LENGTH]; char user[MAX_NAME_LENGTH]; char server[MAX_NAME_LENGTH]; char database_name[MAX_NAME_LENGTH]; char table_name[MAX_NAME_LENGTH]; char query_create_table[MAX_QUERY_LENGTH]; char query_create_db[MAX_QUERY_LENGTH]; char query_data[MAX_QUERY_LENGTH]; }T_MYSQL; void finish_with_error(MYSQL *con); int t_mysql_init(T_MYSQL *mysql); int t_mysql_connect(T_MYSQL *mysql); int t_mysql_disconnect(T_MYSQL *mysql); int t_mysql_createdb(T_MYSQL *mysql); int t_mysql_createtable(T_MYSQL *mysql); int t_mysql_setdb(T_MYSQL *mysql); int t_mysql_insertdata(T_MYSQL *mysql); int t_mysql_quickinsert(T_MYSQL *mysql); #endif /* T_MYSQL_H_ */ </code></pre> t-mysql.c: <pre><code>#include <stdio.h> #include <mysql.h> #include <my_global.h> #include "t-mysql.h" void finish_with_error(MYSQL *con){ fprintf(stderr, "%s\n", mysql_error(con)); mysql_close(con); //close connection to database } int t_mysql_init(T_MYSQL *mysql){ mysql->con = mysql_init(NULL); if (mysql->con == NULL){ finish_with_error(mysql->con); return 0; } return 1; } int t_mysql_connect(T_MYSQL *mysql){ // connect to MySQL if (mysql_real_connect(mysql->con, mysql->server, mysql->user, mysql->password,NULL, 0, NULL, 0) == NULL){ finish_with_error(mysql->con); return 0; } return 1; } int t_mysql_disconnect(T_MYSQL *mysql){ mysql_close(mysql->con); if ( mysql->con == NULL){ finish_with_error(mysql->con); return 0; } return 1; } int t_mysql_createdb(T_MYSQL *mysql){ t_mysql_disconnect(mysql); //disconnect normal user //connect as root t_mysql_init(mysql); if (mysql_real_connect(mysql->con, mysql->server, "root", mysql->root_password,NULL, 0, NULL, 0) == NULL){ finish_with_error(mysql->con); return 0; } // create DB, if it doesn't exist if (mysql_select_db(mysql->con, mysql->database_name)){ if (mysql_query(mysql->con, mysql->query_create_db)){ finish_with_error(mysql->con); return 0; } else { fprintf(stdout,"Database %s created\n",mysql->database_name); } }else{ fprintf(stdout,"Database %s exists\n",mysql->database_name); } //disconnect root user t_mysql_disconnect(mysql); //connect as normal user t_mysql_init(mysql); t_mysql_connect(mysql); return 1; } int t_mysql_setdb(T_MYSQL *mysql){ if (mysql_select_db(mysql->con, mysql->database_name) == NULL){ finish_with_error(mysql->con); return 0; } return 1; } int t_mysql_createtable(T_MYSQL *mysql){ //create table: if(mysql_query(mysql->con, mysql->query_create_table)){ finish_with_error(mysql->con); return 0; } return 1; } int t_mysql_insertdata(T_MYSQL *mysql){ if (mysql_query(mysql->con, mysql->query_data)) { finish_with_error(mysql->con); return 0; } return 1; } </code></pre>
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How can I verify if database is set
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