3
7^L                 @   sp   d dl Z d dlmZ d dlmZ d dlmZ d dlmZ d dl	m
Z
 d dlmZ d dlmZ G d	d
 d
eZdS )    N)Decimal)Apps)BaseDatabaseSchemaEditor)	Statement)UniqueConstraint)atomic)NotSupportedErrorc                   s   e Zd ZdZdZdZdZdZ fddZ fdd	Z	d
d Z
d$ddZd% fdd	Zd& fdd	Zd'ddZd( fdd	Zdd Zdd Zd)ddZdd Z fd d!Z fd"d#Z  ZS )*DatabaseSchemaEditorzDROP TABLE %(table)sNzEREFERENCES %(to_table)s (%(to_column)s) DEFERRABLE INITIALLY DEFERREDz7CREATE UNIQUE INDEX %(name)s ON %(table)s (%(columns)s)zDROP INDEX %(name)sc                s   | j j stdt j S )NzSQLite schema editor cannot be used while foreign key constraint checks are enabled. Make sure to disable them before entering a transaction.atomic() context because SQLite does not support disabling them in the middle of a multi-statement transaction.)
connectiondisable_constraint_checkingr   super	__enter__)self)	__class__ C/tmp/pip-build-8app2_gc/Django/django/db/backends/sqlite3/schema.pyr      s    
zDatabaseSchemaEditor.__enter__c                s(   | j j  t j||| | j j  d S )N)r
   Zcheck_constraintsr   __exit__enable_constraint_checking)r   exc_type	exc_value	traceback)r   r   r   r   !   s    
zDatabaseSchemaEditor.__exit__c             C   s   ydd l }|j|}W n( tk
r*   Y n |jk
r>   Y nX t|trVtt|S t|tt	tfrnt|S t|trd|j
dd S |d krdS t|tttfrd|j  S td|t|f d S )Nr   z'%s''z''ZNULLzX'%s'z*Cannot quote parameter value %r of type %s)sqlite3ZadaptImportErrorZProgrammingError
isinstanceboolstrintr   floatreplacebytes	bytearray
memoryviewhex
ValueErrortype)r   valuer   r   r   r   quote_value&   s$    

z DatabaseSchemaEditor.quote_valueFc       
      C   s   | j j z}xr| j jj|D ]`}|r0|j|kr0q| j jj||j}x8|j D ],}|d \}}	||krL|dkst|	|krLdS qLW qW W dQ R X dS )a  
        Return whether or not the provided table name is referenced by another
        one. If `column_name` is specified, only references pointing to that
        column are considered. If `ignore_self` is True, self-referential
        constraints are ignored.
        Zforeign_keyNTF)r
   cursorZintrospectionZget_table_listnameZ_get_foreign_key_constraintsvalues)
r   
table_nameZcolumn_nameignore_selfr(   Zother_tableconstraints
constraintZconstraint_tableZconstraint_columnr   r   r   _is_referenced_by_fk_constraintB   s    z4DatabaseSchemaEditor._is_referenced_by_fk_constraintTc                sh   | j jj rT|rT| j|rT| j jr.td| | j j  t j||| | j j	  nt j||| d S )NzRenaming the %r table while in a transaction is not supported on SQLite < 3.26 because it would break referential integrity. Try adding `atomic = False` to the Migration class.)
r
   features!supports_atomic_references_renamer/   in_atomic_blockr   r   r   alter_db_tabler   )r   modelZold_db_tableZnew_db_tabledisable_constraints)r   r   r   r3   U   s    
z#DatabaseSchemaEditor.alter_db_tablec                sP  |j }|jj}|j \}}|j |ko>| jjj o>| j||ddr8| jjr^t	d|jj|f t
| jj t j||||d | jj |}	|	jdj d }
|	jd d| }|j d	 }|| }|| }|	jd
||f |	jd|
d	   |	jd |	jd W d Q R X W d Q R X | jj }	|	jd W d Q R X nt j||||d d S )NT)r,   zRenaming the %r.%r column while in a transaction is not supported on SQLite < 3.26 because it would break referential integrity. Try adding `atomic = False` to the Migration class.)strictzPRAGMA schema_versionr   zPRAGMA writable_schema = 1z REFERENCES "%s" ("%%s")    z3UPDATE sqlite_master SET sql = replace(sql, %s, %s)zPRAGMA schema_version = %dzPRAGMA writable_schema = 0zPRAGMA integrity_checkZVACUUM)r)   _metadb_tableZget_attname_columnr
   r0   r1   r/   r2   r   r   aliasr   alter_fieldr(   executeZfetchone)r   r4   	old_field	new_fieldr6   Zold_field_namer+   _Zold_column_namer(   Zschema_versionZreferences_templateZnew_column_namesearchreplacement)r   r   r   r;   d   s4    


z DatabaseSchemaEditor.alter_fieldc                sZ  fddfddj jD }fddj jD }i d}t|dds`|rt|d	 ddrx<t|j D ],\}}	|	jrnd|	_|	}|	jrn||= ||	j= qnW |r|||j< |j	 r|j
rЈjj|||j< |rb|\}
}|j|
jd |j|
jd |||j< |
jrD|j rDd
j|
jjj|d }|||j< nj|
j||j< |j|
j<  r| j= | j=  j	r jjj jrj jjS t }fddj jD }fddj jD }j j} r fdd|D }tj j}tj|}j jj j|||||d}tdf |}||d< j|d< tj jj| tj|}j jdj j |||||d}tdf |}||d< j|d< tdj j j|}j | j!dj|j jdj"fdd|D dj"|j# jj jf  jdd j$||j jj jdd xj%D ]}j!| q0W g _%|rVd|_dS )a|  
        Shortcut to transform a model from old_model into new_model

        This follows the correct procedure to perform non-rename or column
        addition operations based on SQLite's documentation

        https://www.sqlite.org/lang_altertable.html#caution

        The essential steps are:
          1. Create a table with the updated definition called "new__app_model"
          2. Copy the data from the existing "app_model" table to the new table
          3. Drop the "app_model" table
          4. Rename the "new__app_model" table to "app_model"
          5. Restore any index of the previous "app_model" table.
        c                s   | j o| jj kS )N)Zis_relationremote_fieldr4   )f)r4   r   r   is_self_referential   s    z?DatabaseSchemaEditor._remake_table.<locals>.is_self_referentialc                s$   i | ]} |r|j  n||jqS r   )cloner)   ).0rC   )rD   r   r   
<dictcomp>   s   z6DatabaseSchemaEditor._remake_table.<locals>.<dictcomp>c                s   i | ]} j |j|jqS r   )
quote_namecolumn)rF   rC   )r   r   r   rG      s    Nprimary_keyFr7   zcoalesce(%(col)s, %(default)s))coldefaultc                s   g | ]} fd d|D qS )c                s   g | ]} j ||qS r   )get)rF   n)rename_mappingr   r   
<listcomp>   s    zADatabaseSchemaEditor._remake_table.<locals>.<listcomp>.<listcomp>r   )rF   unique)rO   r   r   rP      s   z6DatabaseSchemaEditor._remake_table.<locals>.<listcomp>c                s   g | ]} fd d|D qS )c                s   g | ]} j ||qS r   )rM   )rF   rN   )rO   r   r   rP      s    zADatabaseSchemaEditor._remake_table.<locals>.<listcomp>.<listcomp>r   )rF   index)rO   r   r   rP      s   c                s   g | ]} j |jkr|qS r   )r)   fields)rF   rR   )delete_fieldr   r   rP      s    )	app_labelr9   unique_togetherindex_togetherindexesr-   appsZMeta
__module__znew__%szNew%sz%INSERT INTO %s (%s) SELECT %s FROM %sz, c             3   s   | ]} j |V  qd S )N)rH   )rF   x)r   r   r   	<genexpr>  s    z5DatabaseSchemaEditor._remake_table.<locals>.<genexpr>)handle_autom2m)r5   T)&r8   Zlocal_concrete_fieldsgetattrlistitemsrJ   auto_createdrI   r)   many_to_manyZconcreter'   Zeffective_defaultpopnullrH   rB   throughdelete_modelr   rV   rW   rX   r-   copydeepcopyrU   r9   r%   rZ   Zobject_name	__bases__create_modelr<   joinr*   r3   deferred_sql)r   r4   create_fieldrT   r;   bodymappingZrestore_pk_fieldr)   fieldr=   r>   Zcase_sqlrY   rV   rW   rX   r-   Z	body_copyZmeta_contentsmetaZ	new_modelsqlr   )rT   rD   r4   rO   r   r   _remake_table   s    











z"DatabaseSchemaEditor._remake_tablec                sl   |rt  j| nV| j| jd| j|jji  x6t| jD ](}t	|t
r<|j|jjr<| jj| q<W d S )Ntable)r   rf   r<   sql_delete_tablerH   r8   r9   r_   rl   r   r   Zreferences_tableremove)r   r4   r]   rr   )r   r   r   rf   2  s    z!DatabaseSchemaEditor.delete_modelc             C   s2   |j r |jjjjr | j|jjS | j||d dS )z
        Create a field on a model. Usually involves adding a column, but may
        involve adding a table instead (for M2M fields).
        )rm   N)rb   rB   re   r8   ra   rj   rs   )r   r4   rp   r   r   r   	add_field?  s    zDatabaseSchemaEditor.add_fieldc             C   sN   |j r"|jjjjrJ| j|jj n(|j| jdd dkr<dS | j||d dS )z
        Remove a field from a model. Usually involves deleting a column,
        but for M2Ms may involve deleting a table.
        )r
   r%   N)rT   )	rb   rB   re   r8   ra   rf   Zdb_parametersr
   rs   )r   r4   rp   r   r   r   remove_fieldI  s    z!DatabaseSchemaEditor.remove_fieldc	       
      C   s   | j jjrb|j|jkrb| j||| j||krb|jr:|jpD|joD|j rb| j| j|j	j
|||S | j|||fd |jr|jr||krx$|jj	jD ]}	|	js| j|	j qW dS )z3Perform a "physical" (non-ManyToMany) field update.)r;   N)r
   r0   Zcan_alter_table_rename_columnrI   Z
column_sqlrB   Zdb_constraintr<   Z_rename_field_sqlr8   r9   rs   rJ   r4   Zrelated_objectsrb   Zrelated_model)
r   r4   r=   r>   Zold_typeZnew_typeZold_db_paramsZnew_db_paramsr6   relr   r   r   _alter_field[  s    
z!DatabaseSchemaEditor._alter_fieldc             C   s   |j jjj|j jjjkrR| j|j j|j jjj|j |j jjj|j fd dS | j|j j | jd| j	|j jjjdj
d|j |j gdj
d|j |j g| j	|j jjjf  | j|j j dS )z*Alter M2Ms to repoint their to= endpoints.)r;   Nz%INSERT INTO %s (%s) SELECT %s FROM %sz, id)rB   re   r8   r9   rs   	get_fieldZm2m_reverse_field_namerj   r<   rH   rk   Zm2m_column_nameZm2m_reverse_namerf   )r   r4   r=   r>   r6   r   r   r   _alter_many_to_manyn  s&    

z(DatabaseSchemaEditor._alter_many_to_manyc                s.   t |tr |jr t j|| n
| j| d S )N)r   r   	conditionr   add_constraintrs   )r   r4   r.   )r   r   r   r     s    z#DatabaseSchemaEditor.add_constraintc                s.   t |tr |jr t j|| n
| j| d S )N)r   r   r~   r   remove_constraintrs   )r   r4   r.   )r   r   r   r     s    z&DatabaseSchemaEditor.remove_constraint)NF)T)F)NNN)T)F)__name__rZ   __qualname__ru   Zsql_create_fkZsql_create_inline_fkZsql_create_uniqueZsql_delete_uniquer   r   r'   r/   r3   r;   rs   rf   rw   rx   rz   r}   r   r   __classcell__r   r   )r   r   r	      s(   
'
 (

#r	   )rg   decimalr   Zdjango.apps.registryr   Zdjango.db.backends.base.schemar   Z!django.db.backends.ddl_referencesr   Zdjango.db.modelsr   Zdjango.db.transactionr   Zdjango.db.utilsr   r	   r   r   r   r   <module>   s   