在iPhone中通过sqlite从数据库中选择值

发布于 2024-11-02 16:28:15 字数 616 浏览 1 评论 0原文

我正在使用 sqlite 开发 iPhone 应用程序。在其中，我有一种方法可以从部分显示的表中检索值。

NSString *sqlQuery = [NSString stringWithFormat: @”select * from %@”, tableName];
If(sqlite3_prepare_v2(db, [sqlQuery UTF8STRING] , -1, &statement, NULL)== SQLITE_OK)
{
While(sqlite3_step(statement) == SQLITE_ROW)
{
}
Sqlite3_finalize(statement);
}

我的疑问是，在 while 循环内我们可以通过表的索引获取列的值，如下代码所示。

NSString *addressField = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
address.text = addressField;

对于一列，我们可以这样检索。就我而言，我不知道要检索的列数。在这种情况下，如何迭代列。请帮帮我。谢谢。

原文

I am developing an iphone application using sqlite. In that, I have a method to retrieve the values from the table which is shown partially.

NSString *sqlQuery = [NSString stringWithFormat: @”select * from %@”, tableName];
If(sqlite3_prepare_v2(db, [sqlQuery UTF8STRING] , -1, &statement, NULL)== SQLITE_OK)
{
While(sqlite3_step(statement) == SQLITE_ROW)
{
}
Sqlite3_finalize(statement);
}

What my doubt is , inside the while loop we can get the values of the column through the index of the table like the following code.

NSString *addressField = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
address.text = addressField;

For one column we can retrieve like this. In my case, I don’t know the number of columns to be retrieved. In this case, how to iterate over the columns. Please help me out.
Thanks.

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丑丑阿 2024-11-09 16:28:15

NSString *sqlQuery = [NSString stringWithFormat: @”select * from %@”, tableName];
If(sqlite3_prepare_v2(db, [sqlQuery UTF8STRING] , -1, &statement, NULL)== SQLITE_OK)
{
While(sqlite3_step(statement) == SQLITE_ROW)
{
int columnCount = YouKnowColumnCount;
NSMutableArray* array = [[NSMutableArray alloc]init];

for( int i=0; i<columnCount ; ++i) {
    [array addObject:[[NSString alloc] initWithUTF8String:(const char *)sqlite3_column_text(statement, i)]];
}
Sqlite3_finalize(statement);
}

像这样的事情取决于你想做什么......

NSString *sqlQuery = [NSString stringWithFormat: @”select * from %@”, tableName];
If(sqlite3_prepare_v2(db, [sqlQuery UTF8STRING] , -1, &statement, NULL)== SQLITE_OK)
{
While(sqlite3_step(statement) == SQLITE_ROW)
{
int columnCount = YouKnowColumnCount;
NSMutableArray* array = [[NSMutableArray alloc]init];

for( int i=0; i<columnCount ; ++i) {
    [array addObject:[[NSString alloc] initWithUTF8String:(const char *)sqlite3_column_text(statement, i)]];
}
Sqlite3_finalize(statement);
}

Something like this it depend what do you want to do ...

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