如何解决尝试获取数据并将其插入sqlite数据库时出错
|| 我正在创建一个使用sqlite数据库保存数据的应用程序,但是当我运行我的应用程序时出现以下错误:@interface TDatabase : NSObject {
sqlite3 *database;
}
+(TDatabase *) shareDataBase;
-(BOOL) createDataBase:(NSString *)DataBaseName;
-(NSString*) GetDatabasePath:(NSString *)database;
-(NSMutableArray *) getAllDataForQuery:(NSString *)sql forDatabase:(NSString *)database;
-(void*) inseryQuery:(NSString *) insertSql forDatabase:(NSString *)database1;
@end
#import \"TDatabase.h\"
#import <sqlite3.h>
@implementation TDatabase
static TDatabase *SampleDataBase =nil;
+(TDatabase*) shareDataBase{
if(!SampleDataBase){
SampleDataBase = [[TDatabase alloc] init];
}
return SampleDataBase;
}
-(NSString *)GetDatabasePath:(NSString *)database1{
[self createDataBase:database1];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
return [documentsDirectory stringByAppendingPathComponent:database1];
}
-(BOOL) createDataBase:(NSString *)DataBaseName{
BOOL success;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:DataBaseName];
success = [fileManager fileExistsAtPath:writableDBPath];
if (success) return success;
NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:DataBaseName];
success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
if (!success) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@\"Error!!!\" message:@\"Failed to create writable database\" delegate:self cancelButtonTitle:@\"Cancel\" otherButtonTitles:nil];
[alert show];
[alert release];
}
return success;
}
-(NSMutableArray *) getAllDataForQuery:(NSString *)sql forDatabase:(NSString *)database1{
sqlite3_stmt *statement = nil ;
NSString *path = [self GetDatabasePath:database1];
NSMutableArray *alldata;
alldata = [[NSMutableArray alloc] init];
if(sqlite3_open([path UTF8String],&database) == SQLITE_OK )
{
NSString *query = sql;
if((sqlite3_prepare_v2(database,[query UTF8String],-1,&statement,NULL)) == SQLITE_OK)
{
while(sqlite3_step(statement) == SQLITE_ROW)
{
NSMutableDictionary *currentRow = [[NSMutableDictionary alloc] init];
int count = sqlite3_column_count(statement);
for (int i=0; i < count; i++) {
char *name = (char*) sqlite3_column_name(statement,i);
char *data = (char*) sqlite3_column_text(statement,i);
NSString *columnData;
NSString *columnName = [NSString stringWithCString:name encoding:NSUTF8StringEncoding];
if(data != nil)
columnData = [NSString stringWithCString:data encoding:NSUTF8StringEncoding];
else {
columnData = @\"\";
}
[currentRow setObject:columnData forKey:columnName];
}
[alldata addObject:currentRow];
}
}
sqlite3_finalize(statement);
}
sqlite3_close(database);
return alldata;
}
-(void*) inseryQuery:(NSString *) insertSql forDatabase:(NSString *)database1{
sqlite3_stmt *statement = nil ;
NSString *path = [self GetDatabasePath:database1];
if(sqlite3_open([path UTF8String],&database) == SQLITE_OK )
{
if((sqlite3_prepare_v2(database,[insertSql UTF8String],NULL)) == SQLITE_OK)
{
if(sqlite3_step(statement) == SQLITE_OK){
}
}
sqlite3_finalize(statement);
}
sqlite3_close(database);
return insertSql;
}
NSString *sql = @\"select * from Location\";
const location = [[TDatabase shareDataBase] getAllDataForQuery:sql forDatabase:@\"journeydatabase.sqlite\"];//1
NSString* insertSql = [NSString stringWithFormat:@\"insert into Location values (\'city\',\'name\',\'phone\')\"];//2
const insert =[[TDatabase shareDataBase] inseryQuery:insertSql forDatabase:@\"journeydatabase.sqlite\"];//3
在第1,2,3行中,我得到相同的错误:\“初始化元素不是常量\”
可能是什么问题。请有人帮助我解决这个问题。
谢谢
解决方法
@rani编写自己的方法来处理sqlite数据库是非常艰苦的。您应该使用fmdb包装器类或使用核心数据。我个人更喜欢fmdb。最初,我的行为与您相同。我在这里找到有关fmdb的信息。使用它之后,每当我要处理sqlite db时,我都必须编写很少的代码。
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