sqlite學習筆記10:C語言中使用sqlite之查詢和更新資料,sqlite學習筆記
前面說到的 sqlite_exec() 中的第三個參數, SQLite 將為 sql 參數內執行的每個 SELECT 語句中處理的每個記錄調用這個回呼函數。
本節添加了兩個函數,selectFromTable和updateTable.
執行個體程式如下:
#include <stdio.h>#include <stdlib.h>#include "sqlite/sqlite3.h"#define DB_NANE "sqlite/test.db"sqlite3 *db = NULL;char* sql = NULL;char *zErrMsg = NULL;const char* data = "Callback function called";/* 改為全域的 */int ret = 0;typedef enum{ false, true} bool;/*typedef int (*sqlite3_callback)(void*, Data provided in the 4th argument of sqlite3_exec()int, The number of columns in rowchar**, An array of strings representing fields in the rowchar** An array of strings representing column names);*/static int callback(void *NotUsed, int argc, char **argv, char **azColName){ int i = 0; for(i=0; i < argc; i++){ printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL"); } printf("\n"); return 0;}bool connectDB(){ ret = sqlite3_open(DB_NANE, &db); if( ret != SQLITE_OK){ fprintf(stderr, "Error open database: %s\n", sqlite3_errmsg(db)); sqlite3_free(zErrMsg); return false; } fprintf(stdout, "Successfully opened database\n"); return true;}bool createTable(){ /* Create SQL statement */ sql = "CREATE TABLE COMPANY(" \ "ID INT PRIMARY KEY NOT NULL," \ "NAME TEXT NOT NULL," \ "AGE INT NOT NULL," \ "ADDRESS CHAR(50)," \ "SALARY REAL );"; /* Execute SQL statement */ ret = sqlite3_exec(db, sql, callback, 0, &zErrMsg); if( ret != SQLITE_OK ){ fprintf(stderr, "Error SQL: %s\n", zErrMsg); sqlite3_free(zErrMsg); return false; } fprintf(stdout, "Successfully table created\n"); return true;}bool insertRecords(){ /* Create SQL statement */ sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " \ "VALUES (1, 'Paul', 32, 'California', 20000.00 ); " \ "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " \ "VALUES (2, 'Allen', 25, 'Texas', 15000.00 ); " \ "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)" \ "VALUES (3, 'Teddy', 23, 'Norway', 20000.00 );" \ "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)" \ "VALUES (4, 'Mark', 25, 'Rich-Mond ', 65000.00 );"; /* Execute SQL statement */ ret = sqlite3_exec(db, sql, callback, 0, &zErrMsg); if( ret != SQLITE_OK ){ fprintf(stderr, "SQL error: %s\n", zErrMsg); sqlite3_free(zErrMsg); return false; } fprintf(stdout, "successfully records created\n"); return true;}
bool selectFromTable()/*新加*/{ /* Create SQL statement */ sql = "SELECT * from COMPANY"; /* Execute SQL statement */ ret = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg); if( ret != SQLITE_OK ){ fprintf(stderr, "Error SQL: %s\n", zErrMsg); sqlite3_free(zErrMsg); return false; } fprintf(stdout, "successfully operation done\n"); return true;}
bool updateTable()/* 新加 */{ /* Create merged SQL statement */ sql = "UPDATE COMPANY set SALARY = 25000.00 where ID=1; " \ "SELECT * from COMPANY"; /* Execute SQL statement */ ret = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg); if( ret != SQLITE_OK ){ fprintf(stderr, "SQL error: %s\n", zErrMsg); sqlite3_free(zErrMsg); return false; } fprintf(stdout, "Successfully operation done \n"); return true;}
bool closeDB(){ int ret = 0; ret = sqlite3_close(db); if ( ret == SQLITE_BUSY ){ return false; } return true;}int main(int argc, char* argv[]){ connectDB(); /*createTable();*/ /*insertRecords();*/ selectFromTable(); updateTable(); selectFromTable(); closeDB(); return 0;}
C與sqlite資料庫互連,問怎進行資料更新,
小型案頭資料庫,可選選擇access,或者嵌入式資料庫SQLite(不要裝服務) 建議(5)Access支援ODBC(開發資料庫互連,Open Data Base Connectivity),利用
sqlite3 怎查詢資料庫中所有的表 用C語言實現
SELECT name FROM sqlite_master
WHERE type='table'
ORDER BY name;
在C語言中用這個查詢語句