func main() {
keySpace, err := gocassa.ConnectToKeySpace("test", []string{"127.0.0.1"}, "", "")
if err != nil {
panic(err)
}
salesTable := keySpace.MapTable("sale", "Id", &Sale{})
// Create the table - we ignore error intentionally
salesTable.Create()
// We insert the first record into our table - yay!
err = salesTable.Set(Sale{
Id: "sale-1",
CustomerId: "customer-1",
SellerId: "seller-1",
Price: 42,
Created: time.Now(),
}).Run()
if err != nil {
panic(err)
}
result := Sale{}
if err := salesTable.Read("sale-1", &result).Run(); err != nil {
panic(err)
}
}
func main() {
keySpace, err := gocassa.ConnectToKeySpace("test", []string{"127.0.0.1"}, "", "")
if err != nil {
panic(err)
}
// "SellerId" is the field we will use to query sales:
// MultimapTable enables us to return all the sales where SellerId equals
// to a certain value.
salesTable := keySpace.MultimapTable("sale", "SellerId", "Id", &Sale{})
// Create the table - we ignore error intentionally
salesTable.Create()
// We insert the first record into our table - yay!
err = salesTable.Set(Sale{
Id: "sale-1",
CustomerId: "customer-1",
SellerId: "seller-1",
Price: 42,
Created: time.Now(),
}).Run()
if err != nil {
panic(err)
}
result := Sale{}
// One thing we have to notice here is that to read a single row,
// we have to know the SellerId and SaleId as well. This is due to how
// data is structured in cassandra .
if err := salesTable.Read("seller-1", "sale-1", &result).Run(); err != nil {
panic(err)
}
// As an upside, now we can actually list rows based on a criteria. Let's insert an other row
// before Listing - it is no fun to have a list with one element only ;)
err = salesTable.Set(Sale{
Id: "sale-2",
CustomerId: "customer-1",
SellerId: "seller-1",
Price: 55,
Created: time.Now(),
}).Run()
if err != nil {
panic(err)
}
resultList := []Sale{}
if err := salesTable.List("seller-1", nil, 0, &resultList).Run(); err != nil {
panic(err)
}
// To Update we also need to know both SellerId and SaleId:
fmt.Printf("Updating sales with SellerId %v and Id %v \"sale-1\" with Price = 110\n", "seller-1", "sale-1")
err = salesTable.Update("seller-1", "sale-1", map[string]interface{}{
"Price": 110,
}).Run()
if err != nil {
panic(err)
}
// Read the row again:
if err := salesTable.Read("seller-1", "sale-1", &result).Run(); err != nil {
panic(err)
}
// You might also wonder how paging works.
// With cassandra, the idiomatic way is not page number based paging, but
// rather, you continue the next page where the last one stopped.
// To achieve this, you usually query 1 more result than you need, let's say 21,
// and use the last element as a "cursor"
// Insert some data to paginate:
for i := 0; i < 50; i++ {
err = salesTable.Set(Sale{
Id: fmt.Sprintf("sale-%v", i),
CustomerId: "customer-1",
SellerId: "seller-1",
Price: 55,
Created: time.Now(),
}).Run()
if err != nil {
panic(err)
}
}
err = salesTable.List("seller-1", nil, 11, &resultList).Run()
if err != nil {
panic(err)
}
if len(resultList) > 10 {
err = salesTable.List("seller-1", resultList[10].Id, 11, &resultList).Run()
if err != nil {
panic(err)
}
}
}