1/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7    http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15#include "tensorflow/core/kernels/data/sql/sqlite_query_connection.h"
16
17#include "tensorflow/core/framework/register_types.h"
18#include "tensorflow/core/kernels/data/dataset.h"
19#include "tensorflow/core/lib/strings/stringprintf.h"
20
21namespace tensorflow {
22
23namespace sql {
24
25SqliteQueryConnection::SqliteQueryConnection() {}
26
27SqliteQueryConnection::~SqliteQueryConnection() {
28  if (db_ != nullptr) db_->Unref();
29}
30
31Status SqliteQueryConnection::Open(const string& data_source_name,
32                                   const string& query,
33                                   const DataTypeVector& output_types) {
34  if (db_ != nullptr) {
35    return errors::FailedPrecondition(
36        "Failed to open query connection: Connection already opened.");
37  }
38  TF_RETURN_IF_ERROR(Sqlite::Open(
39      data_source_name, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, &db_));
40  query_ = query;
41  output_types_ = output_types;
42  return Status::OK();
43}
44
45Status SqliteQueryConnection::Close() {
46  stmt_ = SqliteStatement();
47  db_->Unref();
48  db_ = nullptr;
49  return Status::OK();
50}
51
52Status SqliteQueryConnection::GetNext(IteratorContext* ctx,
53                                      std::vector<Tensor>* out_tensors,
54                                      bool* end_of_sequence) {
55  if (!stmt_) TF_RETURN_IF_ERROR(PrepareQuery());
56  TF_RETURN_IF_ERROR(stmt_.Step(end_of_sequence));
57  if (!*end_of_sequence) {
58    for (int i = 0; i < column_count_; i++) {
59      DataType dt = output_types_[i];
60      // TODO(mrry): Pass in the `IteratorContext::allocator()`.
61      Tensor tensor(ctx->allocator({}), dt, {});
62      FillTensorWithResultSetEntry(dt, i, &tensor);
63      out_tensors->emplace_back(std::move(tensor));
64    }
65  }
66  return Status::OK();
67}
68
69Status SqliteQueryConnection::PrepareQuery() {
70  TF_RETURN_IF_ERROR(db_->Prepare(query_, &stmt_));
71  int column_count = stmt_.ColumnCount();
72  if (column_count != output_types_.size()) {
73    stmt_ = SqliteStatement();
74    return errors::InvalidArgument(tensorflow::strings::Printf(
75        "The number of columns in query (%d) must match the number of "
76        "elements in output_types (%zu).",
77        column_count, output_types_.size()));
78  }
79  column_count_ = column_count;
80  return Status::OK();
81}
82
83void SqliteQueryConnection::FillTensorWithResultSetEntry(
84    const DataType& data_type, int column_index, Tensor* tensor) {
85#define CASE(T, M)                                                 \
86  case DataTypeToEnum<T>::value:                                   \
87    tensor->scalar<T>()() = static_cast<T>(stmt_.M(column_index)); \
88    break;
89#define INT_CASE(T) CASE(T, ColumnInt)
90#define DOUBLE_CASE(T) CASE(T, ColumnDouble)
91#define STRING_CASE(T) CASE(T, ColumnString)
92  // clang-format off
93  switch (data_type) {
94    TF_CALL_int8(INT_CASE)
95    TF_CALL_uint8(INT_CASE)
96    TF_CALL_int16(INT_CASE)
97    TF_CALL_uint16(INT_CASE)
98    TF_CALL_int32(INT_CASE)
99    TF_CALL_uint32(INT_CASE)
100    TF_CALL_int64(INT_CASE)
101    TF_CALL_uint64(INT_CASE)
102    TF_CALL_float(DOUBLE_CASE)
103    TF_CALL_double(DOUBLE_CASE)
104    TF_CALL_string(STRING_CASE)
105    case DT_BOOL:
106      tensor->scalar<bool>()() = stmt_.ColumnInt(column_index) != 0;
107      break;
108    // Error preemptively thrown by SqlDatasetOp::MakeDataset in this case.
109    default:
110      LOG(FATAL)
111          << "Use of unsupported TensorFlow data type by 'SqlQueryConnection': "
112          << DataTypeString(data_type) << ".";
113  }
114  // clang-format on
115}
116
117}  // namespace sql
118
119}  // namespace tensorflow
120