// Create and insert the sample puzzles and sample session
func insertSamples(tx *pgx.Tx) error {
// idempotency: if the sample session already exists, we are done
var count int64
row := tx.QueryRow("SELECT COUNT(*) FROM sessions "+
"WHERE sessionId = $1", SampleSessionName)
if err := row.Scan(&count); err != nil {
return fmt.Errorf("Database error looking for session %q: %v", SampleSessionName, err)
}
if count > 0 {
return nil
}
// get the timestamp of this load
now := time.Now()
// first save the puzzles
for i, sum := range samplePuzzles {
values := make([]int32, len(sum.Values))
for i, v := range sum.Values {
values[i] = int32(v) // use 4-byte ints in database
}
_, err := tx.Exec(
"INSERT INTO puzzles (puzzleId, geometry, sideLength, valueList, created) "+
"VALUES ($1, $2, $3, $4, $5)",
sampleHashes[i], sum.Geometry, int32(sum.SideLength), values, now)
if err != nil {
return fmt.Errorf("Database error saving sample puzzle %d: %v", i, err)
}
}
// next save the session
_, err := tx.Exec(
"INSERT INTO sessions (sessionId, created, updated, active) "+
"VALUES ($1, $2, $3, $4)",
SampleSessionName, now, now, sampleHashes[0])
if err != nil {
return fmt.Errorf("Database error saving sample session: %v", err)
}
// next save the session entries
for i := range samplePuzzles {
_, err := tx.Exec(
"INSERT INTO sessionEntries (sessionId, puzzleId, puzzleName, lastView) "+
"VALUES ($1, $2, $3, $4)",
SampleSessionName, sampleHashes[i], sampleNames[i], now)
if err != nil {
return fmt.Errorf("Database error saving sample session puzzle %d: %v", i, err)
}
}
return nil
}
// Delete the common puzzles
func deleteSamples(tx *pgx.Tx) error {
// first remove the puzzle summaries from the database
_, err := tx.Exec(
"DELETE from sessionEntries where sessionId = $1", SampleSessionName)
if err != nil {
return fmt.Errorf("Database error deleting sample session: %v", err)
}
// then remove the session
_, err = tx.Exec(
"DELETE from sessions where sessionId = $1", SampleSessionName)
if err != nil {
return fmt.Errorf("Database error deleting sample session: %v", err)
}
// then remove the puzzles themselves
for i, hash := range sampleHashes {
_, err := tx.Exec(
"DELETE from puzzles where puzzleId = $1", hash)
if err != nil {
return fmt.Errorf("Database error deleting sample puzzle %d: %v", i, err)
}
}
return nil
}