c语言更新数据,sqlite学习笔记10：C语言中使用sqlite之查询和更新数据
前面說到的 sqlite_exec() 中的第三個參數(shù)， SQLite 將為 sql 參數(shù)內執(zhí)行的每個 SELECT 語句中處理的每個記錄調用這個回調函數(shù)。
本節(jié)添加了兩個函數(shù)，selectFromTable和updateTable.
實例程序如下：
#include
#include
#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";/* 改為全局的 */
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 row
char**, An array of strings representing fields in the row
char** 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;
}
原文：http://blog.csdn.net/xufeng0991/article/details/38598313
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