计数SQLite数据库中的行数 [英] Count Number of Rows in a SQLite Database

问题描述

我尝试下面的代码来计算我的SQLite数据库表中的行数，但它抛出一个异常。这是更简单的方法吗？

I'm trying the following code to count the number of rows in my SQLite database table, but it throws an exception. Is these a simpler way to do this?

- (void) countRecords {
    int rows = 0;
    @try {
            NSString *dbPath = [self getDBPath];

            if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK) {

                NSString *strSQL;
                strSQL = @"SELECT COUNT(*) FROM MYTABLE";
                const char *sql = (const char *) [strSQL UTF8String];
                sqlite3_stmt *stmt;

                if (sqlite3_prepare_v2(database, sql, -1, &stmt, NULL) == SQLITE_OK) {

                    // THIS IS WHERE IT FAILS:

                    if (SQLITE_DONE!=sqlite3_step(stmt) ) {

                        NSAssert1(0,@"Error when counting rows  %s",sqlite3_errmsg(database));

                    } else {
                        rows = sqlite3_column_int(stmt, 0);
                        NSLog(@"SQLite Rows: %i", rows);
                    }

                    sqlite3_finalize(stmt);
                }

                sqlite3_close(database);

            }

        }

        @catch (NSException * e) {
        NSLog(@"Error Counting");
        }
}

推荐答案

I遇到一个解决方案，使用我的代码上面，只是替换下面的代码步骤语句：

I came across a solution, using my code above, just replacing the step statement with the code below:

if (sqlite3_step(stmt) == SQLITE_ERROR) {
    NSAssert1(0,@"Error when counting rows  %s",sqlite3_errmsg(database));
} else {
    rows = sqlite3_column_int(stmt, 0);
    NSLog(@"SQLite Rows: %i", rows);
}

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