Component: Database
=================
This component is provided by the [[item:database_upgrade|database upgrade]].

Component name: `database`.  

The database component is primarily useful to work with "full" item stacks, including NBT tags, which are (by default) not available to Lua scripts (to avoid exploits / breaking of other mods' gameplay). Some components allow specifying item stacks by instead specifying the address of a database component, and slot the item stack is in that database - for example, the Export Bus driver for Applied Energistics 2 makes use of this functionality.

Callbacks:

- `get(slot:number):table`  
  Get the representation of the item stack stored in the specified slot.
- `computeHash(slot:number):string`  
  Computes a hash value for the item stack in the specified slot. This value is guaranteed to be the same for identical item stacks, allowing comparison of item stacks across a network (by comparing the hash values).
- `indexOf(hash:string):number`  
  Get the index of an item stack with the specified hash. Returns a negative value if no such stack was found.
- `clear(slot:number):boolean`  
  Clears the specified slot. Returns true if there was something in the slot before.
- `copy(fromSlot:number, toSlot:number[, address:string]):boolean`  
  Copies an entry to another slot, optionally to another database. Returns true if something was overwritten.
- `clone(address:string):number`  
  Copies the data stored in this database to another database with the specified address.


Example Use:

```lua
local component = require("component")
local sides = require("sides")

local db = component.database -- primary database component
local invcontrol = component.inventory_controller -- primary inventory controller

-- define slot numbers
dbSlot = 1
invSlot = 1

-- compare item inside remote inventory to item in first slot of database
if db.get(dbSlot).label == invcontrol.getStackInSlot(sides.north, invSlot).label then
	-- items match, do stuff with it. 
else
	-- items don't match, do nothing, or do something else.
end
```
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