3.write_read_delete.cpp

#include <iostream>

#include <terark/db/db_table.hpp>
#include <terark/io/MemStream.hpp>
#include <terark/io/DataIO.hpp>
#include <terark/io/RangeStream.hpp>
#include <terark/lcast.hpp>

#include "user.hpp"

// g++-4.9 -std=c++1y 3.write_read_delete.cpp -lterark-db-r -lboost_system -lterark-fsa_all-r -lboost_filesystem -Iinclude
// Write data into user_table 
int main(){
  std::cout<<"Hello Terark, We will write data into db.user_table"<<std::endl;

  // open table
  static const char* dbtable = "db/user_table";
  terark::db::CompositeTablePtr tab = terark::db::CompositeTable::open(dbtable);

  // write data (1000 records)
  terark::NativeDataOutput<terark::AutoGrownMemIO> rowBuilder;
  terark::db::DbContextPtr ctx = tab->createDbContext();

  test_ns::User u = {};

  int count = 1000;
  for(int i = 1; i <= count; i++) {
    u.id = i;
    u.name = "TestName " + i;
    u.description = "Description " + i;
    u.age = (i + 10);
    u.update_time = 1463472964753 + i;
    // insert row
    rowBuilder.rewind();
    rowBuilder<<u;
    terark::fstring binRow(rowBuilder.begin(), rowBuilder.tell());
    if (ctx->insertRow(binRow) < 0) {
      printf("Insert failed: %s\n", ctx->errMsg.c_str());
    }
  }

  // read data(1000 records)
  terark::valvec<terark::byte> nameVal;     // column value
  terark::valvec<terark::byte> descVal;     // column value
  terark::valvec<terark::llong> idvec;               // id vector of index

  size_t indexId = tab->getIndexId("id");

  size_t nameColumnId = tab->getColumnId("name");
  size_t descColumnId = tab->getColumnId("description");

  std::cout<<"name colId = "<<nameColumnId<<", desc colId ="<<descColumnId<<std::endl;

  if (indexId >= tab->getIndexNum()) {
    fprintf(stderr, "ERROR: index 'id' does not exist\n");
    terark::db::CompositeTable::safeStopAndWaitForCompress();
    return 0;
  }

  // iterate ids, read name and description values
  for(int i = 1; i <= count; i++) {
    terark::fstring key = terark::fstring((char*)&i, 4);
    ctx->indexSearchExact(indexId, key, &idvec);
    // print ids
    // std::cout<<tab->getIndexSchema(indexId).toJsonStr(key).c_str()<<std::endl;
    for (auto recId : idvec) {
      ctx->selectOneColumn(recId, nameColumnId, &nameVal);
      ctx->selectOneColumn(recId, descColumnId, &descVal);
      printf("%.*s  ", (int)nameVal.size(), nameVal.data());
      printf("%.*s\n", (int)descVal.size(), descVal.data());
    }
  }

  // delete data(1000 records)
  for(int i = 1; i <= count; i++) {
    terark::fstring key = terark::fstring((char*)&i, 4);
    ctx->indexSearchExact(indexId, key, &idvec);
    for (auto recId : idvec) {
      ctx->removeRow(recId);
      // std::cout<<"delete row : "<<recId<<std::endl;
    }
  }

  // close table
  terark::db::CompositeTable::safeStopAndWaitForCompress();
  return 0;
}