database::query_builder Class Reference

Universal query builder that adapts to different database types. More...

#include <query_builder.h>

Collaboration diagram for database::query_builder:

Public Member Functions
	query_builder (database_types db_type=database_types::none)
	~query_builder ()=default
	query_builder (query_builder &&) noexcept=default
query_builder &	operator= (query_builder &&) noexcept=default
	query_builder (const query_builder &)=delete
query_builder &	operator= (const query_builder &)=delete
query_builder &	for_database (database_types db_type)
query_builder &	select (const std::vector< std::string > &columns)
query_builder &	from (const std::string &table)
query_builder &	where (const std::string &field, const std::string &op, const core::database_value &value)
query_builder &	where (const query_condition &condition)
query_builder &	join (const std::string &table, const std::string &condition, join_type type=join_type::inner)
query_builder &	order_by (const std::string &column, sort_order order=sort_order::asc)
query_builder &	group_by (const std::vector< std::string > &columns)
query_builder &	group_by (const std::string &column)
query_builder &	having (const std::string &condition)
query_builder &	limit (size_t count)
query_builder &	offset (size_t count)
query_builder &	insert_into (const std::string &table)
query_builder &	values (const std::map< std::string, core::database_value > &data)
query_builder &	values (const std::vector< std::map< std::string, core::database_value > > &rows)
query_builder &	update (const std::string &table)
query_builder &	set (const std::string &field, const core::database_value &value)
query_builder &	set (const std::map< std::string, core::database_value > &data)
query_builder &	delete_from (const std::string &table)
query_builder &	collection (const std::string &name)
query_builder &	key (const std::string &key)
std::string	build () const
core::database_result	execute (core::database_backend *db) const
void	reset ()
database_types	get_database_type () const

Private Member Functions
void	ensure_dialect ()

Private Attributes
database_types	db_type_
std::unique_ptr< query_dialect >	dialect_

Detailed Description

Universal query builder that adapts to different database types.

This class provides a unified interface for building queries across different database backends (PostgreSQL, SQLite, MongoDB, Redis) using the Strategy pattern.

Thread Safety

• NOT thread-safe. Each thread should use its own instance.
• Create separate builders for each thread or protect with external mutex.

Memory Efficiency

• Only allocates ONE dialect instance per builder.
• Dialect is lazily initialized when first needed.

Example Usage

// SQL query
query_builder builder(database_types::postgres);
auto query = builder
    .select({"id", "name"})
    .from("users")
    .where("active", "=", true)
    .order_by("name")
    .limit(10)
    .build();
 
// Switch database type
builder.for_database(database_types::sqlite);
auto sqlite_query = builder.select({"*"}).from("users").build();

Definition at line 104 of file query_builder.h.

Constructor & Destructor Documentation

query_builder() [1/3]

database::query_builder::query_builder ( database_types db_type = database_types::none )

explicit

Definition at line 163 of file query_builder.cpp.

        : db_type_(db_type)
    {
        ensure_dialect();
    }

References ensure_dialect().

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~query_builder()

database::query_builder::~query_builder ( )

default

query_builder() [2/3]

database::query_builder::query_builder ( query_builder && )

defaultnoexcept

query_builder() [3/3]

database::query_builder::query_builder ( const query_builder & )

delete

Member Function Documentation

build()

std::string database::query_builder::build

(

)

const

Definition at line 357 of file query_builder.cpp.

    {
        if (dialect_) {
            return dialect_->build();
        }
        return "";
    }

References dialect_.

Referenced by execute(), main(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), and TEST_F().

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collection()

query_builder & database::query_builder::collection

(

const std::string &

name

)

Definition at line 339 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_collection(name);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

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delete_from()

query_builder & database::query_builder::delete_from

(

const std::string &

table

)

Definition at line 330 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_delete_table(table);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main().

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ensure_dialect()

void database::query_builder::ensure_dialect ( )

private

Definition at line 395 of file query_builder.cpp.

    {
        if (!dialect_ && db_type_ != database_types::none) {
            dialect_ = create_dialect(db_type_);
        }
    }

References database::create_dialect(), db_type_, dialect_, and database::none.

Referenced by collection(), delete_from(), for_database(), from(), group_by(), having(), insert_into(), join(), key(), limit(), offset(), order_by(), query_builder(), select(), set(), set(), update(), values(), values(), where(), and where().

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execute()

core::database_result database::query_builder::execute

(

core::database_backend *

db

)

const

Definition at line 365 of file query_builder.cpp.

    {
        if (!db) {
            return {};
        }
 
        std::string query = build();
        if (query.empty()) {
            return {};
        }
 
        auto result = db->select_query(query);
        if (result.is_err()) {
            return {};
        }
        return result.value();
    }

References build(), and database::core::database_backend::select_query().

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for_database()

query_builder & database::query_builder::for_database

(

database_types

db_type

)

Definition at line 169 of file query_builder.cpp.

    {
        if (db_type_ != db_type) {
            db_type_ = db_type;
            dialect_.reset();
            ensure_dialect();
        }
        return *this;
    }

References db_type_, dialect_, and ensure_dialect().

Referenced by main(), database::tests::TEST_F(), database::tests::TEST_F(), and database::tests::TEST_F().

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from()

query_builder & database::query_builder::from

(

const std::string &

table

)

Definition at line 188 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_from_table(table);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by database::tests::TEST_F().

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get_database_type()

database_types database::query_builder::get_database_type

(

)

const

Definition at line 390 of file query_builder.cpp.

    {
        return db_type_;
    }

References db_type_.

group_by() [1/2]

query_builder & database::query_builder::group_by

(

const std::string &

column

)

Definition at line 242 of file query_builder.cpp.

    {
        return group_by(std::vector<std::string>{column});
    }

References group_by().

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group_by() [2/2]

query_builder & database::query_builder::group_by

(

const std::vector< std::string > &

columns

)

Definition at line 233 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_group_by(columns);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by group_by(), and main().

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having()

query_builder & database::query_builder::having

(

const std::string &

condition

)

Definition at line 247 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_having(condition);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main().

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insert_into()

query_builder & database::query_builder::insert_into

(

const std::string &

table

)

Definition at line 274 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_insert_table(table);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), and database::tests::TEST_F().

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join()

query_builder & database::query_builder::join	(	const std::string &	table,
		const std::string &	condition,
		join_type	type = join_type::inner )

Definition at line 215 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->add_join(table, condition, type);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), and database::tests::TEST_F().

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key()

query_builder & database::query_builder::key

(

const std::string &

key

)

Definition at line 348 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_key(key);
        }
        return *this;
    }

References dialect_, ensure_dialect(), and key().

Referenced by key().

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limit()

query_builder & database::query_builder::limit

(

size_t

count

)

Definition at line 256 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_limit(count);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), TEST_F(), and TEST_F().

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offset()

query_builder & database::query_builder::offset

(

size_t

count

)

Definition at line 265 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_offset(count);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main().

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operator=() [1/2]

query_builder & database::query_builder::operator= ( const query_builder & )

delete

operator=() [2/2]

query_builder & database::query_builder::operator= ( query_builder && )

defaultnoexcept

order_by()

query_builder & database::query_builder::order_by	(	const std::string &	column,
		sort_order	order = sort_order::asc )

Definition at line 224 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->add_order_by(column, order);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), database::tests::TEST_F(), and TEST_F().

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reset()

void database::query_builder::reset

(

)

Definition at line 383 of file query_builder.cpp.

    {
        if (dialect_) {
            dialect_->reset();
        }
    }

References dialect_.

Referenced by main(), database::tests::TEST_F(), and TEST_F().

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select()

query_builder & database::query_builder::select

(

const std::vector< std::string > &

columns

)

Definition at line 179 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_select_columns(columns);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), and TEST_F().

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set() [1/2]

query_builder & database::query_builder::set

(

const std::map< std::string, core::database_value > &

data

)

Definition at line 321 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_update_data(data);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

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set() [2/2]

query_builder & database::query_builder::set	(	const std::string &	field,
		const core::database_value &	value )

Definition at line 310 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            std::map<std::string, core::database_value> data;
            data[field] = value;
            dialect_->set_update_data(data);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), and database::tests::TEST_F().

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update()

query_builder & database::query_builder::update

(

const std::string &

table

)

Definition at line 301 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_update_table(table);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), and database::tests::TEST_F().

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values() [1/2]

query_builder & database::query_builder::values

(

const std::map< std::string, core::database_value > &

data

)

Definition at line 283 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_insert_data(data);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), and database::tests::TEST_F().

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values() [2/2]

query_builder & database::query_builder::values

(

const std::vector< std::map< std::string, core::database_value > > &

rows

)

Definition at line 292 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->set_insert_rows(rows);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

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where() [1/2]

query_builder & database::query_builder::where

(

const query_condition &

condition

)

Definition at line 206 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->add_where_condition(condition);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

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where() [2/2]

query_builder & database::query_builder::where	(	const std::string &	field,
		const std::string &	op,
		const core::database_value &	value )

Definition at line 197 of file query_builder.cpp.

    {
        ensure_dialect();
        if (dialect_) {
            dialect_->add_where_condition(field, op, value);
        }
        return *this;
    }

References dialect_, and ensure_dialect().

Referenced by main(), database::tests::TEST_F(), database::tests::TEST_F(), database::tests::TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), TEST_F(), and TEST_F().

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Member Data Documentation

db_type_

database_types database::query_builder::db_type_

private

Definition at line 160 of file query_builder.h.

Referenced by ensure_dialect(), for_database(), and get_database_type().

dialect_

std::unique_ptr<query_dialect> database::query_builder::dialect_

private

Definition at line 161 of file query_builder.h.

Referenced by build(), collection(), delete_from(), ensure_dialect(), for_database(), from(), group_by(), having(), insert_into(), join(), key(), limit(), offset(), order_by(), reset(), select(), set(), set(), update(), values(), values(), where(), and where().

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The documentation for this class was generated from the following files:

• database/query_builder.h
• database/query_builder.cpp