SQLite使用(二)

sqlite3_exec虽然好用，但是一般不推荐直接使用。

常用的一组操作是:

关于sqlite3_exec和sqlite3_prepare_v2的使用场景，建议如下：

一个小DEMO:

#include <stdio.h>
#include <sqlite3.h>

int main(int argc, char **argv)
{
    sqlite3 *db;
    int rc;
    
    rc = sqlite3_open("test.db", &db);
    
    if (rc) {
        printf("Can't open database: %s
", sqlite3_errmsg(db));
        sqlite3_close(db);
        return 1;
    } else {
        printf("Open database successfully
");
    }
    
    sqlite3_stmt *stmt = NULL;
    
    const char *sql = "SELECT * FROM COMPANY";
//    const char *sql = "SELECT * FROM COMPANY WHERE AGE=?;";
    
    sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
    
//    sqlite3_bind_int(stmt, 1, 25);

    int col_count = sqlite3_column_count(stmt);
    printf("该条记录共%d列
", col_count);
    
    while (SQLITE_ROW == sqlite3_step(stmt)) {
        int column0_type = sqlite3_column_type(stmt, 0);
        const char *column0_name = sqlite3_column_name(stmt, 0);
        int column0_value = sqlite3_column_int(stmt, 0);
        printf("col: 0 type: %d name: %-10s value: %d
", column0_type, column0_name, column0_value);
        
        int column1_type = sqlite3_column_type(stmt, 1);
        const char *column1_name = sqlite3_column_name(stmt, 1);
        const unsigned char *column1_value = sqlite3_column_text(stmt, 1);
        printf("col: 1 type: %d name: %-10s value: %s
", column1_type, column1_name, column1_value);
        
        int column2_type = sqlite3_column_type(stmt, 2);
        const char *column2_name = sqlite3_column_name(stmt, 2);
        int column2_value = sqlite3_column_int(stmt, 2);
        printf("col: 2 type: %d name: %-10s value: %d
", column2_type, column2_name, column2_value);
        
        int column3_type = sqlite3_column_type(stmt, 3);
        const char *column3_name = sqlite3_column_name(stmt, 3);
        const unsigned char *column3_value = sqlite3_column_text(stmt, 3);
        printf("col: 3 type: %d name: %-10s value: %s
", column3_type, column3_name, column3_value);
        
        int column4_type = sqlite3_column_type(stmt, 4);
        const char *column4_name = sqlite3_column_name(stmt, 4);
        double column4_value = sqlite3_column_double(stmt, 4);
        printf("col: 4 type: %d name: %-10s value: %.2f
", column4_type, column4_name, column4_value);
        
        printf("
");
    }
    sqlite3_finalize(stmt);
    
//    char *zErrMsg = 0;
//    sqlite3_stmt *stmt_insert;
//    const char *sql_insert = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) "  
//    "VALUES (5, 'Logan', 26, 'California', 20000.00 );";
//    sqlite3_prepare_v2(db, sql_insert, -1, &stmt_insert, NULL);
//    if (sqlite3_step(stmt_insert) != SQLITE_DONE) {
//        printf("Insert Table Failed
");
//        sqlite3_free(zErrMsg);
//    }
//    sqlite3_finalize(stmt_insert);
    
    sqlite3_close(db);
    return 0;
}

参考资料:

sqlite3_prepare_v2 / sqlite3_exec

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