C language and the creation and use of database

c Creation and use of language and database

data.h The header file

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data.c Implementation file

/*  Main program data processing source file  */#include <stdio.h>#include <sqlite3.h>#include <time.h>#include <sys/types.h>#include <unistd.h>/********************************************************************************************** *    :|x].              ?ObU:        +jfl           ?Zdr'                   '"I>>iI"'         *    n$$${             [email protected]$$k;       n$$$Mi         [B$$$c               "-xZ*%$$$$$%*pX+      *    >8$$k`           j$$$C^       ]$$$$$Q.       `k$$$$8l            ~Y#$$%kQznnuY0qhk|      *     j$$$n          {@$$0'       .q$$$$$B<       ($$$$$$/          'uB$$p{:                  *     'm$$B+        +&$$b,        [email protected]$$B$$$z      ;#$$8%$$Z.         +$$$M:                    *      !&$$b^      !*$$#!         C$$$\k$$M:    [email protected]}X$$8!         ,w$$$bc|}-~<iI".          *       f$$$x     :k$$&+         _B$$p./$$$x    /$$$u [email protected]$$x          '[[email protected]$$$$$$$%oOr>       *       'w$$%~   ^w$$B}         `[email protected] "h$$Wl  _8$$O' 'p$$o"             ^:!><+](n0#[email protected]>     *        >8$$b^ 'L$$$\          x$$$C   )$$$C Io$$a;   ($$$t                       `[#$$*:    *         /$$$X.c$$$x          <8$$&l   [email protected]\w$$%+    "a$$#;     ,]]"               p$$$>    *         [email protected]$$$Y.         .O$$$n     >8$$$$$$t      \$$$J     0$$*\"         '!(p$$$u.    *          "d$$$$$Q'          >B$$%i      r$$$$$L.      ^[email protected]{    _b$$$&qJvnnncCq#$$$&Q-      *           lh$$$Y'           [$$$U       `[email protected]^        {@$$a^    .+jQk&@[email protected]&aOn[:        *            :\r]             '{x)^        .+}>           ?UJ).         ^:l>>>l:^.             *                                                                                            *********************************************************************************************/#include <sys/wait.h>#include <string.h>#include <stdlib.h>#include <signal.h>#include <pthread.h>#include "data.h"#define DATABASE_NAME "user.db"#define TABLE_USER "user"pthread_mutex_t db_mutex;sqlite3 *db;      // database /*  Add a user  *//*  After the client sends the registration request , The server side registers user information into the database  */int db_add_user(char name[], char passwd[]){    char *errmsg;    char sqlstr[1024] = {0};    if ((name == NULL) || (passwd == NULL))    {        printf("Invalid name or password entered.\r\n");        return -1;    }    if ((strlen(name) > 32) || (strlen(passwd) > 32))    {        printf("The entered name or password is too long.\r\n");        return -1;    }    sprintf(sqlstr, "insert into %s values('%s', '%s',-1, 1,0)",            TABLE_USER, name, passwd);    if (sqlite3_exec(db, sqlstr, NULL, NULL, &errmsg) != 0)    {        printf("Database query error: %s\r\n", sqlite3_errmsg(db));    }    else    {        //printf("User added successfully.\r\n");    }    //printf("\r\n");    return 1;}/*  Determine whether a user name is registered  *//*   function ： Determine whether a user name is registered      Return value ： Return with name index, Otherwise return to -1 */int db_user_if_reg(char *name){    int state = -1;    char **result, *errmsg;    int nrow, ncolumn, i, j, index;    char sqlstr[1024] = {0};    sprintf(sqlstr, "select regist from %s where name='%s'",            TABLE_USER, name);    if (sqlite3_get_table(db, sqlstr, &result, &nrow, &ncolumn, &errmsg) != 0)    {        printf("Database query error: %s\r\n", errmsg);        sqlite3_free(errmsg);    }    index = ncolumn;    if (nrow > 0)    {        // Find the user with the specified name in the database ( data ), At least one piece of data         state = 1;    }    else    {        // No user with the specified name was found in the database ( data )        state = -1;    }    sqlite3_free_table(result);    return state;}/*  Determine whether the user name and password are correct  */int db_user_pwd_corrct(char *name, char *passwd){    int state = -1;    char **result, *errmsg;    int nrow, ncolumn, i, j, index;    char sqlstr[1024] = {0};    sprintf(sqlstr, "select * from %s where name='%s' and passwd='%s'",            TABLE_USER, name, passwd);    /* function ： perform SQL operation        Parameters ：  db： Database handle             sql：SQL sentence             resultp： Used for pointing sql Pointer to the execution result             nrow： The number of records that satisfy the condition             ncolumn： Number of fields per record             errmsg： The address of the error message pointer      Return value ：  Successfully returns 0, Failure return error code     */    if (sqlite3_get_table(db, sqlstr, &result, &nrow, &ncolumn, &errmsg) != 0)    {        printf("Database query error: %s\r\n", errmsg);        sqlite3_free(errmsg);        return -1;    }    index = ncolumn;    if (nrow > 0)    {        // Find the user with the specified name and password in the database ( data )        state = 1;    }    else    {        // The user with the specified name and password was not found in the database ( data )               state = -1;    }    sqlite3_free_table(result);    return state;}/*  Database initialization  */int database_init(){    int n;    int ret;    char *errmsg;    char sql[] =        "CREATE TABLE IF NOT EXISTS user(name INT PRIMARY KEY   NOT NULL,passwd TEXT    NOT NULL,fd INT NOT NULL,regist INT  NOT NULL,keygen INT);";    pthread_mutex_init(&db_mutex, NULL);    if (sqlite3_open(DATABASE_NAME, &db) < 0)    {        printf("Failed to open sqlite3: %s\r\n", sqlite3_errmsg(db));        return -1;    }    /*  Use the callback function to perform SQL sentence  */    ret = sqlite3_exec(db, sql, NULL, 0, &errmsg);    if (ret != SQLITE_OK)    {        fprintf(stderr, "Database query error: %s\r\n", errmsg);        sqlite3_free(errmsg);    }    else    {        fprintf(stdout, "The database initialized successfully.\r\n");    }    return 0;}/*  Close the database  */void database_close(){    sqlite3_close(db);}

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