Question

Creating an Iphone application, I used to perform INSERT QUERY on different databases.
But when I tried inserting the data in the same database, it gives me assertion failure.
I am reading two different XML URL and trying to create and then insert the data in the table as it is read by creating DB. Does anyone have idea why does this show me error ?
I have the following code which does insert on DB using SQLITE:

  -(void) insertProductTable:(NSMutableArray *)Dict{
[Dict retain];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *dbPath = [documentsDirectory stringByAppendingPathComponent:@"product.sql"];
NSInteger i;

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

    const char * insert_product_sql = "INSERT OR REPLACE INTO test(ID,KEY ) VALUES (?,?)" ;
    if(sqlite3_prepare_v2(database, insert_product_sql, -1, &product_statement, nil) != SQLITE_OK){
        NSAssert1(0, @"Error: failed to prepare insert_product_sql: '%s'.", sqlite3_errmsg(database));
    }

    for (i = 0; i < [self.array count]; i++) {
     sqlite3_bind_text(product_statement, 1, [[Dict valueForKey:@"ID"] UTF8String] ,-1, SQLITE_TRANSIENT);
     sqlite3_bind_text(product_statement, 2, [[Dict valueForKey:@"KEY"] UTF8String] ,-1, SQLITE_TRANSIENT);
    }

    if (sqlite3_step(product_statement) != SQLITE_DONE) {
        NSAssert(0,@"Error updating table");
    }

    [Dict release]; Dict = 0;
    sqlite3_finalize(product_statement);
    sqlite3_close(database);

}
}

I have the following method which does the different insert function but different table but at this stage it doesnot allow me to insert throwing me Assertion Failure. Both the methods are called by different class.

    -(void) insertTable:(NSMutableArray *)Dict{
[Dict retain];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *dbPath = [documentsDirectory stringByAppendingPathComponent:@"product.sql"];
NSInteger i;

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

    const char * insert_sql = "INSERT OR REPLACE INTO test1(Term,Value ) VALUES (?,?)" ;
    if(sqlite3_prepare_v2(database, insert_sql, -1, &product_statement, nil) != SQLITE_OK){
        NSAssert1(0, @"Error: failed to prepare insert_sql: '%s'.", sqlite3_errmsg(database));
    }

    for (i = 0; i < [self.arayList count]; i++) {
     sqlite3_bind_text(product_statement, 1, [[Dict valueForKey:@"TERM"] UTF8String] ,-1, SQLITE_TRANSIENT);
     sqlite3_bind_text(product_statement, 2, [[Dict valueForKey:@"VALUE"] UTF8String] ,-1, SQLITE_TRANSIENT);
    }

    if (sqlite3_step(product_statement) != SQLITE_DONE) {
        NSAssert(0,@"Error updating table");
    }

    [Dict release]; Dict = 0;

    sqlite3_finalize(product_statement);
    sqlite3_close(database);

}
}

Answer 1

@lifemoveson

I used to your code to debug and found that the function

sqlite3_prepare_v2(database, insert_product_sql, -1, &product_statement, nil)

returns 1 everytime and it corresponds to your missing database at the desired location.

What I will suggest to you is make a function such as this

-(void)checkAndCreateDatabase{
    databaseName = @"MasterDB.sqlite";
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = [documentPaths objectAtIndex:0];
    databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
    NSLog(@"database path %@",databasePath);
    BOOL success;

    // Create a FileManager object, we will use this to check the status
    // of the database and to copy it over if required
    NSFileManager *fileManager = [NSFileManager defaultManager];

    // Check if the database has already been created in the users filesystem
    success = [fileManager fileExistsAtPath:databasePath];

    // If the database already exists then return without doing anything
    if(success) return;

    // If not then proceed to copy the database from the application to the users filesystem

    // Get the path to the database in the application package
    NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:databaseName];

    // Copy the database from the package to the users filesystem
    [fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];
    //[fileManager release];

    // Now we can add new table

    sqlite3 *database;
    sqlite3_stmt *statement; 
    if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK)
    {

        NSString *sqlQuery = [NSString stringWithFormat:@"CREATE TABLE IF NOT EXISTS tbl_Login (userId integer PRIMARY KEY,userName text,password text);"] ;
        const char *create_stmt = [sqlQuery UTF8String];
        sqlite3_prepare_v2(database, create_stmt, -1, &statement, NULL);

        if(sqlite3_step(statement)==SQLITE_DONE) 
        {
            NSLog(@"Table created");            
        }
        else 
        {
            NSLog(@"Table could not be created");
        }   
        // Release the compiled statement from memory
        sqlite3_finalize(statement);    
        sqlite3_close(database);
    }
}

Which sets your class variable databasePath and ensure that before you run any database query the database is actually present in the applcation’s document directory. You can call this function in application delegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
//Other code 
[self checkAndCreateDatabase];

}

When you make any database call use this

const char *dbpath = [databasePath UTF8String];
    if (sqlite3_open(dbpath , &database) == SQLITE_OK) {
//Code to perform insert operations
 }

i would suggest you to write a separate class for all the database operation that you perform and instead call the class function to achieve the desired functionality. This will save your efforts from rewriting the code.

You can make use of FMDB wrapper for this which you can find here

Hope this helps 🙂