litesql::Database Class Reference

A base class of databases. More...

#include <database.hpp>

Classes
class	SchemaItem
	intermediate representation of single entity in relational database, table, index or sequence More...

Public Member Functions
	Database (const std::string &backendType, const std::string &connInfo)
	opens connection to backend, throw exception if fails or cannot found a Backend class More...
	Database (const Database &op)
	opens new connection to same database More...
virtual	~Database ()
	closes database
void	create () const
	creates database based on getSchema
void	drop () const
	converts CREATE-statements (of getSchema) to DROP statements and executes them
bool	needsUpgrade () const
	returns true if schema of backend database is different from schema returned by getSchema.
void	upgrade () const
	tries to upgrade database on disk so that schemas would be compatible
Records	query (const std::string &query) const
	executes SQL query More...
template<class T >
Cursor< T >	cursor (const std::string &query) const
void	insert (const std::string &table, const Record &r, const std::vector< std::string > &fields=std::vector< std::string >()) const
	executes SQL INSERT statement. More...
std::string	groupInsert (const Record &tables, const Records &fields, const Records &values, const std::string &sequence) const
	executes multiple INSERT-statements and assigns same 'row id' for first field of every record More...
void	delete_ (const std::string &table, const Expr &e=Expr()) const
	deletes rows from single table, deleted rows are selected by Expr if specified More...
void	begin () const
	begins SQL transaction
void	commit () const
	commits SQL transaction
void	rollback () const
	cancels active SQL transaction

Public Attributes
bool	verbose
	verbosity, prints queries to cerr if true

Protected Member Functions
void	storeSchemaItem (const SchemaItem &s) const
	stores SchemaItem to 'schema' - table (deletes old versions)
virtual std::vector< SchemaItem >	getSchema () const
	returns database schema. More...
std::vector< SchemaItem >	getCurrentSchema () const
	queries 'schema' - table and converts results to SchemaItem-objects More...
void	upgradeTable (const std::string &name, const std::string &oldSchema, const std::string &newSchema) const
	adds missing and removes extra fields to/from table (tries to preserve data). More...
bool	addColumn (const std::string &name, const ColumnDefinition &column_def) const

Protected Attributes
std::unique_ptr< Backend >	backend
	backend implementation

Friends
class	Updater

Detailed Description

A base class of databases.

Can be used without inheriting own version of Database using query()-method. See Defining Database

Constructor & Destructor Documentation

Database() [1/2]

litesql::Database::Database	(	const std::string &	backendType,
		const std::string &	connInfo
	)

opens connection to backend, throw exception if fails or cannot found a Backend class

Parameters

backendType	backend type ("postgresql","mysql" or "sqlite3")
connInfo	connection params, syntax "param=value param=value ..." valid keys: host,user,password,database and port

Database() [2/2]

Database::Database

(

const Database &

op

)

opens new connection to same database

Parameters

op	opened Database

Member Function Documentation

delete_()

void Database::delete_	(	const std::string &	table,
		const Expr &	e = Expr()
	)		const

deletes rows from single table, deleted rows are selected by Expr if specified

Parameters

table	target table
e	selection expression

References query().

Referenced by storeSchemaItem().

getCurrentSchema()

vector< Database::SchemaItem > Database::getCurrentSchema ( ) const

protected

queries 'schema' - table and converts results to SchemaItem-objects

Returns

SchemaItem-objects

References query().

Referenced by needsUpgrade(), and upgrade().

getSchema()

virtual std::vector<SchemaItem> litesql::Database::getSchema ( ) const

inlineprotectedvirtual

returns database schema.

Returns

SchemaItem-objects

Referenced by create(), drop(), needsUpgrade(), and upgrade().

groupInsert()

string Database::groupInsert	(	const Record &	tables,
		const Records &	fields,
		const Records &	values,
		const std::string &	sequence
	)		const

executes multiple INSERT-statements and assigns same 'row id' for first field of every record

Parameters

tables	destination tables for insert operation
fields	record of field names per table
values	record of values per table
sequence	sequence where row id-numbers are pulled

Returns

new row id

References backend, litesql::join(), and verbose.

Referenced by litesql::Persistent::insert().

insert()

void Database::insert	(	const std::string &	table,
		const Record &	r,
		const std::vector< std::string > &	fields = std::vector<std::string>()
	)		const

executes SQL INSERT statement.

Parameters

table	destination table
r	values
fields	field names Values are escaped using escapeSQL - function

References litesql::escapeSQL(), litesql::join(), and query().

Referenced by storeSchemaItem().

query()

Records Database::query

(

const std::string &

query

)

const

executes SQL query

Parameters

query

query std::string

Returns

result set

References backend, and verbose.

Referenced by litesql::DataSource< T >::count(), create(), delete_(), drop(), getCurrentSchema(), insert(), upgrade(), and upgradeTable().

upgradeTable()

void Database::upgradeTable ( const std::string &  name, const std::string &  oldSchema, const std::string &  newSchema  ) const

protected

adds missing and removes extra fields to/from table (tries to preserve data).

copies data to a temporary table and then back to upgraded table because all backends do not support ALTER TABLE ADD ... - SQL statements.

Parameters

name	table name
oldSchema	current schema of table
newSchema	upgraded schema of table

References begin(), commit(), litesql::join(), and query().

Referenced by upgrade().

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

• database.hpp
• database.cpp