1 /**

     2  * Relational pipes

     3  * Copyright © 2019 František Kučera (Frantovo.cz, GlobalCode.info)

     4  *

     5  * This program is free software: you can redistribute it and/or modify

     6  * it under the terms of the GNU General Public License as published by

     7  * the Free Software Foundation, version 3.

     8  *

     9  * This program is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

    12  * GNU General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU General Public License

    15  * along with this program. If not, see <http://www.gnu.org/licenses/>.

    16  */

    17 

    18 #include "PreparedStatement.h"

    19 

    20 namespace relpipe {

    21 namespace tr {

    22 namespace sql {

    23 

    24 PreparedStatement::PreparedStatement(sqlite3_stmt* stmt) : stmt(stmt) {

    25 }

    26 

    27 PreparedStatement::~PreparedStatement() {

    28 	sqlite3_finalize(stmt);

    29 }

    30 

    31 void PreparedStatement::setBoolean(int parameterIndex, relpipe::reader::boolean_t value) {

    32 	int result = sqlite3_bind_int(stmt, parameterIndex, value);

    33 	if (result != SQLITE_OK) throw SqlException(L"Unable to set SQLite parameter.");

    34 }

    35 

    36 void PreparedStatement::setInteger(int parameterIndex, relpipe::reader::integer_t value) {

    37 	int result = sqlite3_bind_int64(stmt, parameterIndex, value);

    38 	if (result != SQLITE_OK) throw SqlException(L"Unable to set SQLite parameter.");

    39 }

    40 

    41 void PreparedStatement::setString(int parameterIndex, std::string value) {

    42 	int result = sqlite3_bind_text(stmt, parameterIndex, value.c_str(), -1, SQLITE_TRANSIENT);

    43 	if (result != SQLITE_OK) throw SqlException(L"Unable to set SQLite parameter.");

    44 }

    45 

    46 void PreparedStatement::setNull(int parameterIndex) {

    47 	int result = sqlite3_bind_null(stmt, parameterIndex);

    48 	if (result != SQLITE_OK) throw SqlException(L"Unable to set SQLite parameter.");

    49 }

    50 

    51 bool PreparedStatement::next() {

    52 	int result = sqlite3_step(stmt);

    53 	if (result == SQLITE_ROW) return true;

    54 	else if (result == SQLITE_DONE) return false;

    55 	else throw SqlException(L"Error while iterating over SQLite result.");

    56 }

    57 

    58 void PreparedStatement::reset() {

    59 	int result = sqlite3_reset(stmt);

    60 	if (result != SQLITE_OK) throw SqlException(L"Unable to reset SQLite prepared statement.");

    61 }

    62 

    63 int PreparedStatement::getColumnCount() {

    64 	return sqlite3_column_count(stmt);

    65 }

    66 

    67 std::string PreparedStatement::getColumName(int columnIndex) {

    68 	const char* name = sqlite3_column_name(stmt, columnIndex);

    69 	if (name) return name;

    70 	else throw SqlException(L"Unable to get SQLite column name.");

    71 }

    72 

    73 relpipe::writer::TypeId PreparedStatement::getColumType(int columnIndex, relpipe::writer::TypeId defaultType) {

    74 	const char* type = sqlite3_column_decltype(stmt, columnIndex);

    75 

    76 	// TODO: sqlite3_column_decltype returns value only for columns of existing tables, not for dynamic expressions – SQLite uses dynamic types

    77 	// maybe we could write a function/module that returns result set metadata for given query (before executing it)

    78 	// or use at least explicit casts in SQL and modify sqlite3_column_decltype() function or add some new one to return such casted type

    79 	// 

    80 	// fprintf(stderr, "%d → %s\n", columnIndex, type);

    81 	// SELECT typeof(1+1); == "integer"

    82 	// https://www.sqlite.org/c3ref/column_decltype.html – sqlite3_column_decltype

    83 	// https://www.sqlite.org/c3ref/column_blob.html – sqlite3_column_type

    84 	// https://www.sqlite.org/datatype3.html – Datatypes In SQLite Version 3

    85 	// https://dba.stackexchange.com/questions/203220/sqlite-what-is-the-use-of-specifying-data-types

    86 	// https://www.mail-archive.com/sqlite-users@mailinglists.sqlite.org/msg118093.html

    87 

    88 	if (type == nullptr) return relpipe::writer::TypeId::STRING;

    89 	else if (strcmp(type, "integer") == 0) return relpipe::writer::TypeId::INTEGER;

    90 	else if (strcmp(type, "text") == 0) return relpipe::writer::TypeId::STRING;

    91 	else return defaultType;

    92 	// TODO: support also other data types

    93 }

    94 

    95 std::string PreparedStatement::getString(int columnIndex) {

    96 	const char* value = (const char*) sqlite3_column_text(stmt, columnIndex);

    97 		return value ? value : ""; // TODO: support NULL values (when supported in relpipe format)

    98 }

    99 

   100 }

   101 }

   102 }