Uploading data simultaneously in sql server 2008

Question

Hi All,
I have a scenario like multiple users loading different data into a tool.Till now my scripts were allowing 1 user to load a data at a time. Now it should allow many users to upload their data simultaneously(or atleast the illusion that the data is being
uploaded at the same time).
IF tables are being locked during an import then as soon as the table is unlocked user 2's data should start processing.
If table locking must occur, l should lock the table until that table is finished being updated. This is the case,First user loads XL spreadsheet which has data into the tool. once it is loaded and import is clicked , In database first 
Assetstaging -------->Centerlinestaging------->Misc_asset are populated these are the main tables which populates first. Then my procedures get executed. At this point i should restrict ,i.e User1 loads the data main table populates,at same time user
2 loads data ,So how will i handle this kind of scenario? I got a hint using locking concept i should do, I am not aware about that..is there any way i can do please help me.I am new to to this.
Deepa

Answer 1

1. First application accepts an XL spreadsheet which has a bulk data
2. Once import is done Staging tables are loaded first. Till now only one user was able to load the data. Now requirement is like multiple users should load different data. I should lock at staging tables. 
I dont have any idea about locking concept. How can i lock the staging table? what should i do when other users are also loading data at same time?
Below is the staging table structure
CREATE TABLE dbo.Misc_AssetTypeStaging
    Point                 int                NULL,
Misc_AssetType        varchar(100)       NULL,
BeginMilepostPrefix   varchar(5)         NULL,
BeginMilepostSuffix   varchar(5)         NULL,
BeginMilepost         decimal(15, 8)     NULL,
BeginTrackName        varchar(20)        NULL,
BeginLatitude         decimal(15, 8)     NULL,
BeginLongitude        decimal(15, 8)     NULL,
BeginElevation        decimal(15, 8)     NULL,
EndLatitude           decimal(15, 8)     NULL,
EndLongitude          decimal(15, 8)     NULL,
EndElevation          decimal(15, 8)     NULL,
EndMilepostPrefix     varchar(5)         NULL,
EndMilepostSuffix     varchar(5)         NULL,
EndMilepost           decimal(15, 8)     NULL,
EndTrackName          varchar(20)        NULL,
SubdivisionName        varchar(20)       NULL,
Direction             varchar(16)        NULL,
    Speed                 int                NULL,
TrainType             varchar(20)        NULL,
Operator              varchar(2)         NULL,
QualifierType         varchar(15)        NULL,
RestrictionParameter  int                NULL,
RestrictionType       varchar(20)        NULL,
FBARDirection        varchar(16)        NULL,
SignalAuthorityType  varchar(16)        NULL,
YardLimits           varchar(1)         NULL,
CabSignalType        varchar(16)        NULL,
PTCType              varchar(15)        NULL
Please help me.Thanks in advance
Deepa