/// <summary>Updates the database to reflect the new values of the changed catalog item elements.</summary>
///
/// <param name="item">The item to update in the databsse</param>
/// <param name="updatedElements">The elements of the item that have changed and therefore should be updated.</param>
public void UpdateItem(SqliteCatalogStoreItem item, StoreItemElements updatedElements)
{
if (!item.Stored) {
throw new ArgumentException("Cannot update an item that has not been saved to the catalog", "item");
}
if (!item.Loaded) {
throw new ArgumentException("Cannot update an item that has not been loaded", "item");
}
try {
item.Persisting = true;
//If any of the simple elements of the catalog_items table have
//changed, update them. It's easier to just update them all
if ((updatedElements & (StoreItemElements.Title |
StoreItemElements.Uri |
StoreItemElements.Type |
StoreItemElements.AliasOf |
StoreItemElements.Parent)) != 0) {
String sql = @"
update catalog_items
set
parent_catalog_item_id = ?,
uri = ?,
title = ?,
type = ?,
alias_catalog_item_id = ?
where
catalog_item_id = ?";
using (SQLiteCommand cmd = _conn.CreateCommand()) {
cmd.CommandType = CommandType.Text;
cmd.CommandText = sql;
cmd.CreateAndAddUnnamedParameters();
cmd.Parameters[0].DbType = DbType.Int64;
if (item.Parent == null || !item.Parent.Stored) {
cmd.Parameters[0].Value = DBNull.Value;
} else {
cmd.Parameters[0].Value = item.Parent.Id;
}
cmd.Parameters[1].DbType = DbType.String;
cmd.Parameters[1].Value = item.Uri;
cmd.Parameters[2].DbType = DbType.String;
cmd.Parameters[2].Value = item.Title;
cmd.Parameters[3].DbType = DbType.String;
cmd.Parameters[3].Value = item.Type;
cmd.Parameters[4].DbType = DbType.Int64;
if (item.AliasOf == null || !item.AliasOf.Stored) {
cmd.Parameters[4].Value = DBNull.Value;
} else {
cmd.Parameters[4].Value = item.AliasOf.Id;
}
cmd.Parameters[5].DbType = DbType.Int64;
cmd.Parameters[5].Value = item.Id;
cmd.ExecuteNonQuery();
}
//If the title has changed, need to rebuild the title graph too
if ((updatedElements & StoreItemElements.Title) != 0) {
SetItemTitleWords(item);
}
}
//If the tags changed, update those
if ((updatedElements & StoreItemElements.Tags) != 0) {
//Delete existing tags, and replace with the new tags
//Realistically, it would be a trivial optimization to
//just update changed tags, delete removed, etc.
String sql = @"delete from catalog_item_tags where catalog_item_id = ?";
using (SQLiteCommand cmd = _conn.CreateCommand()) {
cmd.CommandType = CommandType.Text;
cmd.CommandText = sql;
cmd.CreateAndAddUnnamedParameters();
cmd.Parameters[0].DbType = DbType.Int64;
cmd.Parameters[0].Value = item.Id;
cmd.ExecuteNonQuery();
}
//Now re-create the tags
sql = "insert into catalog_item_tags(catalog_item_id, tag) values (?, ?)";
using (SQLiteCommand cmd = _conn.CreateCommand()) {
cmd.CommandType = CommandType.Text;
cmd.CommandText = sql;
cmd.CreateAndAddUnnamedParameters();
cmd.Prepare();
cmd.Parameters[0].Value = item.Id;
foreach (String tag in item.Tags) {
cmd.Parameters[1].Value = tag;
cmd.ExecuteNonQuery();
}
}
}
//If the alias or children lists change, that's a special case.
//it must mean that another item has changed its AliasOf or
//Parent property. Since the children and aliases lists are
//build from the Parent and AliasOf properties, respectively,
//there's no need to explicitly save these lists; only the items within
//them.
} finally {
item.Persisting = false;
}
}
/// <summary>Updates the database to reflect a change to one of the item's elements.</summary>
///
/// <param name="elements"></param>
private void UpdateElement(StoreItemElements elements)
{
if (_loaded && Stored && !_persisting) {
//Item is already in the database, so update it
_store.Persistor.UpdateItem(this, elements);
}
}
