如何通过iphone项目中的obj c方法改变sqlite数据库中的表 [英] how can i alter table in sqlite database through the obj c methods in iphone project
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问题描述
hii每一个
我需要在现有表中添加一列,以便如何通过obj c更改sqlite数据库中的表,我使用以下内容以相同的方式将数据插入表中的代码如何编写updata表方法
I need to add one column to my existing table so how can i alter table in sqlite database through the obj c ,i am using the following code for inserting data into table in the same way how can i write updata table method
- (void) InsertRecord {
if(addStmt == nil) {
const char *sql = "insert into tbl_Users(FirstName,MiddleName) Values(?,?)";
if(sqlite3_prepare_v2(database, sql, -1, &addStmt, NULL) != SQLITE_OK)
NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(database));
}
sqlite3_bind_text(addStmt, 1, [strFirstName UTF8String], -1, SQLITE_TRANSIENT);
sqlite3_bind_text(addStmt, 2, [strMiddleName UTF8String], -1, SQLITE_TRANSIENT);
//sqlite3_bind_text(addStmt, 3, [strLogin UTF8String], -3, SQLITE_TRANSIENT);
if(SQLITE_DONE != sqlite3_step(addStmt))
NSAssert1(0, @"Error while inserting data. '%s'", sqlite3_errmsg(database));
else
//SQLite provides a method to get the last primary key inserted by using sqlite3_last_insert_rowid
//productID = sqlite3_last_insert_rowid(database);
//Reset the add statement.
sqlite3_reset(addStmt);
}
任何人都可以帮助我,, thanx提前
can any one help me,,thanx in advance
推荐答案
这可能有些用处。
头文件
This might be of some use. Header File
NSString *databasePath;
.m文件
//调用这些方法
.m File //Make a call to these Methods
[self checkAndCreateDB ];
[self alterDB];
-(void)checkAndCreateDB {
NSString* databaseName = @"MasterDB.sqlite";
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
BOOL success1;
NSFileManager *fileManager = [NSFileManager defaultManager];
success1 = [fileManager fileExistsAtPath:databasePath];
if(success1) return;
NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:databaseName];
[fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];
}
-(void) alterDB{
sqlite3 *database;
sqlite3_stmt *statement;
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK)
{
NSString *updateSQL = [NSString stringWithFormat: @"ALTER TABLE User ADD COLUMN testColumn TEXT"];
const char *update_stmt = [updateSQL UTF8String];
sqlite3_prepare_v2(database, update_stmt, -1, &statement, NULL);
if(sqlite3_step(statement)==SQLITE_DONE)
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"DB altered" message:@"Success" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
[alert release];
alert=nil;
}
else
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"DB Updation" message:@"DB not Altered" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
[alert release];
alert=nil;
}
// Release the compiled statement from memory
sqlite3_finalize(statement);
sqlite3_close(database);
}
}
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