ceph/src/rocksdb/examples/column_families_example.cc

   1 // Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5 #include <cstdio>
   6 #include <string>
   7 #include <vector>
   8
   9 #include "rocksdb/db.h"
  10 #include "rocksdb/options.h"
  11 #include "rocksdb/slice.h"
  12
  13 #if defined(OS_WIN)
  14 std::string kDBPath = "C:\\Windows\\TEMP\\rocksdb_column_families_example";
  15 #else
  16 std::string kDBPath = "/tmp/rocksdb_column_families_example";
  17 #endif
  18
  19 using ROCKSDB_NAMESPACE::ColumnFamilyDescriptor;
  20 using ROCKSDB_NAMESPACE::ColumnFamilyHandle;
  21 using ROCKSDB_NAMESPACE::ColumnFamilyOptions;
  22 using ROCKSDB_NAMESPACE::DB;
  23 using ROCKSDB_NAMESPACE::DBOptions;
  24 using ROCKSDB_NAMESPACE::Options;
  25 using ROCKSDB_NAMESPACE::ReadOptions;
  26 using ROCKSDB_NAMESPACE::Slice;
  27 using ROCKSDB_NAMESPACE::Status;
  28 using ROCKSDB_NAMESPACE::WriteBatch;
  29 using ROCKSDB_NAMESPACE::WriteOptions;
  30
  31 int main() {
  32   // open DB
  33   Options options;
  34   options.create_if_missing = true;
  35   DB* db;
  36   Status s = DB::Open(options, kDBPath, &db);
  37   assert(s.ok());
  38
  39   // create column family
  40   ColumnFamilyHandle* cf;
  41   s = db->CreateColumnFamily(ColumnFamilyOptions(), "new_cf", &cf);
  42   assert(s.ok());
  43
  44   // close DB
  45   s = db->DestroyColumnFamilyHandle(cf);
  46   assert(s.ok());
  47   delete db;
  48
  49   // open DB with two column families
  50   std::vector<ColumnFamilyDescriptor> column_families;
  51   // have to open default column family
  52   column_families.push_back(ColumnFamilyDescriptor(
  53       ROCKSDB_NAMESPACE::kDefaultColumnFamilyName, ColumnFamilyOptions()));
  54   // open the new one, too
  55   column_families.push_back(
  56       ColumnFamilyDescriptor("new_cf", ColumnFamilyOptions()));
  57   std::vector<ColumnFamilyHandle*> handles;
  58   s = DB::Open(DBOptions(), kDBPath, column_families, &handles, &db);
  59   assert(s.ok());
  60
  61   // put and get from non-default column family
  62   s = db->Put(WriteOptions(), handles[1], Slice("key"), Slice("value"));
  63   assert(s.ok());
  64   std::string value;
  65   s = db->Get(ReadOptions(), handles[1], Slice("key"), &value);
  66   assert(s.ok());
  67
  68   // atomic write
  69   WriteBatch batch;
  70   batch.Put(handles[0], Slice("key2"), Slice("value2"));
  71   batch.Put(handles[1], Slice("key3"), Slice("value3"));
  72   batch.Delete(handles[0], Slice("key"));
  73   s = db->Write(WriteOptions(), &batch);
  74   assert(s.ok());
  75
  76   // drop column family
  77   s = db->DropColumnFamily(handles[1]);
  78   assert(s.ok());
  79
  80   // close db
  81   for (auto handle : handles) {
  82     s = db->DestroyColumnFamilyHandle(handle);
  83     assert(s.ok());
  84   }
  85   delete db;
  86
  87   return 0;
  88 }