Abstract base class for database-specific SQL dialects. More...

#include <sql_dialect.h>

Inheritance diagram for database::query::sql_dialect:

Collaboration diagram for database::query::sql_dialect:

Public Member Functions
virtual	~sql_dialect ()=default

virtual std::string	placeholder (int index) const =0
	Generate parameter placeholder.

virtual std::string	quote_identifier (std::string_view name) const =0
	Quote an identifier (table or column name)

virtual std::string	escape_string (std::string_view str) const =0
	Escape a string value for safe SQL inclusion.

virtual std::string	returning_clause (std::string_view column="") const =0
	Generate RETURNING clause for INSERT/UPDATE.

virtual std::string	upsert_clause (const std::vector< std::string > &conflict_columns, const std::vector< std::string > &update_columns) const =0
	Generate UPSERT (INSERT OR UPDATE) clause.

virtual std::string	limit_clause (size_t limit, size_t offset) const =0
	Generate LIMIT clause.

virtual std::string	auto_increment () const =0
	Get auto-increment column definition.

virtual std::string	current_timestamp () const =0
	Get current timestamp function.

virtual std::string	concat_operator () const =0
	Get string concatenation operator.

virtual bool	supports_feature (const std::string &feature) const =0
	Check if database supports specific feature.

Static Public Member Functions
static std::unique_ptr< sql_dialect >	create (database_types type)
	Factory method to create appropriate dialect.

Detailed Description

Abstract base class for database-specific SQL dialects.

Strategy Pattern:

Encapsulates database-specific SQL syntax variations
Allows runtime selection of appropriate dialect
Makes it easy to add new database support

Responsibilities:

Placeholder style formatting ($1 vs ?1)
Identifier quoting ("col" vs [col])
LIMIT/OFFSET clause formatting
RETURNING clause support
UPSERT clause formatting
Auto-increment column definition
Current timestamp functions
String escaping
Boolean literals
Data type mappings

Definition at line 36 of file sql_dialect.h.

Constructor & Destructor Documentation

◆ ~sql_dialect()

virtual database::query::sql_dialect::~sql_dialect ( )

virtualdefault

Member Function Documentation

◆ auto_increment()

virtual std::string database::query::sql_dialect::auto_increment ( ) const

pure virtual

Get auto-increment column definition.

Returns: SQL fragment for auto-increment column

Examples:

PostgreSQL: "SERIAL"
SQLite: "AUTOINCREMENT"

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ concat_operator()

virtual std::string database::query::sql_dialect::concat_operator ( ) const

pure virtual

Get string concatenation operator.

Returns: Operator or function for concatenation

Examples:

PostgreSQL: "||"
SQLite: "||"

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ create()

std::unique_ptr< sql_dialect > database::query::sql_dialect::create ( database_types type )

static

Factory method to create appropriate dialect.

Parameters

type	Database type

Returns: Unique pointer to dialect instance

Definition at line 11 of file sql_dialect.cpp.

                                                                  {
    switch (type) {
        case database_types::postgres:
            return std::make_unique<postgresql_dialect>();
        case database_types::sqlite:
            return std::make_unique<sqlite_dialect>();
        default:
            throw std::invalid_argument("Unsupported database type for SQL dialect");
    }
}

References database::postgres, and database::sqlite.

Referenced by database::query::tests::CrossDialectTest::SetUp(), database::query::tests::PostgreSQLDialectTest::SetUp(), database::query::tests::SQLiteDialectTest::SetUp(), database::query::tests::TEST(), database::query::tests::TEST(), and database::query::tests::TEST().

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◆ current_timestamp()

virtual std::string database::query::sql_dialect::current_timestamp ( ) const

pure virtual

Get current timestamp function.

Returns: SQL function for current timestamp

Examples:

PostgreSQL: "CURRENT_TIMESTAMP"
SQLite: "CURRENT_TIMESTAMP"

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ escape_string()

virtual std::string database::query::sql_dialect::escape_string ( std::string_view str ) const

pure virtual

Escape a string value for safe SQL inclusion.

Parameters

str	The string to escape

Returns: Escaped string (without surrounding quotes)

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ limit_clause()

virtual std::string database::query::sql_dialect::limit_clause	(	size_t	limit,
		size_t	offset ) const

pure virtual

Generate LIMIT clause.

Parameters

limit	Maximum number of rows
offset	Number of rows to skip

Returns: Database-specific LIMIT clause

Examples:

PostgreSQL: "LIMIT 10 OFFSET 5"
SQLite: "LIMIT 10 OFFSET 5"

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ placeholder()

virtual std::string database::query::sql_dialect::placeholder ( int index ) const

pure virtual

Generate parameter placeholder.

Parameters

index 1-based parameter index

Returns: Database-specific placeholder string

Examples:

PostgreSQL: "$1", "$2", "$3"
SQLite: "?1", "?2", "?3"

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ quote_identifier()

virtual std::string database::query::sql_dialect::quote_identifier ( std::string_view name ) const

pure virtual

Quote an identifier (table or column name)

Parameters

name	The identifier to quote

Returns: Quoted identifier

Examples:

PostgreSQL: "\"column_name\""
SQLite: "\"column_name\""

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ returning_clause()

virtual std::string database::query::sql_dialect::returning_clause ( std::string_view column = "" ) const

pure virtual

Generate RETURNING clause for INSERT/UPDATE.

Parameters

column The column to return (empty for all)

Returns: Database-specific RETURNING clause or empty if unsupported

Examples:

PostgreSQL: " RETURNING id"
SQLite: " RETURNING id" (3.35+)

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ supports_feature()

virtual bool database::query::sql_dialect::supports_feature ( const std::string & feature ) const

pure virtual

Check if database supports specific feature.

Parameters

feature Feature name

Returns: true if supported

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

◆ upsert_clause()

virtual std::string database::query::sql_dialect::upsert_clause	(	const std::vector< std::string > &	conflict_columns,
		const std::vector< std::string > &	update_columns ) const

pure virtual

Generate UPSERT (INSERT OR UPDATE) clause.

Parameters

conflict_columns	Columns that define conflict
update_columns	Columns to update on conflict

Returns: Database-specific upsert clause

Examples:

PostgreSQL: "ON CONFLICT (id) DO UPDATE SET ..."
SQLite: "ON CONFLICT (id) DO UPDATE SET ..."

Implemented in database::query::postgresql_dialect, and database::query::sqlite_dialect.

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

database/query_builder/sql_dialect.h
database/query_builder/sql_dialect.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~sql_dialect()

Member Function Documentation

◆ auto_increment()

◆ concat_operator()

◆ create()

◆ current_timestamp()

◆ escape_string()

◆ limit_clause()

◆ placeholder()

◆ quote_identifier()

◆ returning_clause()

◆ supports_feature()

◆ upsert_clause()