EOSchemaSynchronization

Implemented by: EOSynchronizationFactory

Package: com.webobjects.eoaccess

Interface Description

EOSQLExpression is an abstract superclass that defines how to build SQL statements for adaptor channels. You don't typically use instances of EOSQLExpression; rather, you use EOSQLExpression subclasses written to work with a particular RDBMS and corresponding adaptor. A concrete subclass of EOSQLExpression overrides many of its methods in terms of the query language syntax for its specific RDBMS. EOSQLExpression objects are used internally by the Framework, and unless you're creating a concrete adaptor, you won't ordinarily need to interact with EOSQLExpression objects yourself. You most commonly create and use an EOSQLExpression object when you want to send an SQL statement directly to the server. In this case, you simply create an expression with EOSQLExpression and send the expression object to an adaptor channel using EOAdaptorChannel's evaluateExpression method.

For more information on using EOSQLExpressions, see the following sections:

Constants

EOSQLExpression defines the following String constants.

Constant Description

SchemaSynchronizationPrimary KeySupportKey Key for use in options dictionaries. A corresponding value of "YES" indicates that the EOSQLExpression should generate SQL to create primary key support.

SchemaSynchronizationPrimary KeyConstraintsKey Key for use in options dictionaries. A corresponding value of "YES" indicates that the EOSQLExpression should generate SQL to create primary key constraints.

SchemaSynchronizationPrimary KeySupportKey Key for use in options dictionaries. A corresponding value of "YES" indicates that the EOSQLExpression should generate SQL to create foreign key constraints.

AllowsNullKey Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.

ColumnNameKey Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.

ExternalNameKey Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.

ExternalTypeKey Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.

NameKey Key for use in change dictionaries. A corresponding value indicates the old value of the table or column.

PrecisionKey Key for use in change dictionaries. A corresponding value indicates the value a column's precision should be changed from.

RelationshipsKey Key for use in change dictionaries. The corresponding value is a dictionary of relationships which have been modified since the last time the model and schema were sychronized. For more information see "The Change Dictionary" (page 306).

ScaleKey Key for use in change dictionaries. A corresponding value indicates the value the column's scale should be changed from.

WidthKey Key for use in change dictionaries. A corresponding value indicates the value the column's width should be changed from.

Method Types

Synchronizing the database with a modelstatementsToUpdateObjectStoreForModel statementsToUpdateObjectStoreForEntityGroups statementsToCopyTableNamed phraseCastingColumnNamed statementsToRenameTableNamed statementsToInsertColumnForAttribute statementsToDeleteColumnNamed statementsToRenameColumnNamed statementsToModifyColumnNullRule statementsToConvertColumnType isColumnTypeEquivalentToColumnType statementsToDropForeignKeyConstraintsOnEntityGroups statementsToDropPrimaryKeyConstraintsOnEntityGroups statementsToDropPrimaryKeySupportForEntityGroups statementsToImplementForeignKeyConstraintsOnEntityGroups statementsToImplementPrimaryKeyConstraintsOnEntityGroups statementsToImplementPrimaryKeySupportForEntityGroupsQuerying about database synchronization supportwsupportsSchemaSynchronization supportsDirectColumnCoercion supportsDirectColumnDeletion supportsDirectColumnInsertion supportsDirectColumnNullRuleModification supportsDirectColumnRenaming

Instance Methods

isColumnTypeEquivalentToColumnType

public abstract boolean isColumnTypeEquivalentToColumnType( EOSchemaSynchronization.ColumnTypes columnTypeA, EOSchemaSynchronization.ColumnTypes columnTypeB, NSDictionary options)

Returns true if values in a column of columnTypeA can be copied into a column of columnTypeB without the use of a casting phrase, false otherwise. The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

objectStoreChangesFromAttribute

public abstract NSDictionary objectStoreChangesFromAttributeToAttribute( EOAttribute anAttribute, EOAttribute anotherAttribute

Description forthcoming.

phraseCastingColumnNamed

public abstract String phraseCastingColumnNamed( String columnName, EOSchemaSynchronization.ColumnTypes fromType, EOSchemaSynchronization.ColumnTypes castType NSDictionary options)

Returns an SQL string to cast the values in the column specified by columnName to a new type. This method is used when the adaptor doesn't support in-place column type coercion, and the table has to be recreated. To move data from the old table to the new table, sometimes a conversion statement is needed (for example, to convert strings in a VARCHAR column to numbers). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToConvertColumnType

public abstract NSArray statementsToConvertColumnType( String columnName, String tableName, EOSchemaSynchronization.ColumnTypes type, EOSchemaSynchronization.ColumnTypes newType, NSDictionary options)

Returns an array of EOSQLExpressions to convert in place the type of the specified column. The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToCopyTableNamed

public abstract NSArray statementsToCopyTableNamed( String tableName, NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to copy the specified table into a new table, whose definition is provided by entityGroup-an array of EOEntity objects rooted to the table named tableName. This method is used when the adaptor doesn't support the in-place table modifications required to synchronize the database to a model.

The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToDeleteColumnNamed

public abstract NSArray statementsToDeleteColumnNamed( String columnName, String tableName, NSDictionary options)

Returns an array of EOSQLExpressions to delete in place the specified column from the specified table. The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToDropForeignKeyConstraintsOnEntityGroups

public abstract NSArray statementsToDropForeignKeyConstraintsOnEntityGroups( NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to drop foreign key constraints for the table corresponding to entityGroup-an array of EOEntity objects rooted to the same table. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToDropPrimaryKeyConstraintsOnEntityGroups

public abstract NSArray statementsToDropPrimaryKeyConstraintsOnEntityGroups( NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to drop primary key constraints for the table corresponding to entityGroup-an array of EOEntity objects rooted to the same table. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToDropPrimaryKeySupportForEntityGroups

public abstract NSArray statementsToDropPrimaryKeySupportForEntityGroups( NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to drop the primary key support mechanism for the table corresponding to entityGroup-an array of EOEntity objects rooted to the same table. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToImplementForeignKeyConstraintsOnEntityGroups

public abstract NSArray statementsToImplementForeignKeyConstraintsOnEntityGroups( NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to implement foreign key constraints on the table corresponding to entityGroup-an array of EOEntity objects rooted to the same table. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToImplementPrimaryKeyConstraintsOnEntityGroups

public abstract NSArray statementsToImplementPrimaryKeyConstraintsOnEntityGroups( NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to implement primary key constraints on the table corresponding to entityGroup-an array of EOEntity objects rooted to the same table. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToImplementPrimaryKeySupportForEntityGroups

public abstract NSArray statementsToImplementPrimaryKeySupportForEntityGroups( NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to implement support mechanisms for primary key generation for the table corresponding to entityGroup-an array of EOEntity objects rooted to the same table. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToInsertColumnForAttribute

public abstract NSArray statementsToInsertColumnForAttribute( EOAttribute attribute, NSDictionary options)

Returns an array of EOSQLExpressions to insert in place a column for the specified attribute. The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToModifyColumnNullRule

public abstract NSArray statementsToModifyColumnNullRule( String columnName, String tableName, boolean allowsNull, NSDictionary options)

Returns an array of EOSQLExpressions to modify in place the specified column to either allow or not allow NULL values as specified by allowsNull. The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToRenameColumnNamed

public abstract NSArray statementsToRenameColumnNamed( String columnName, String tableName, String newName, NSDictionary options)

Returns an array of EOSQLExpressions to rename in place the specified column. The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToRenameTableNamed

public abstract NSArray statementsToRenameTableNamed( String tableName, String newName, NSDictionary options)

Returns an array of EOSQLExpressions to rename in place the specified table. The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToUpdateObjectStoreForEntityGroups

public abstract NSArray statementsToUpdateObjectStoreForEntityGroups( NSArray entityGroup, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to update the table that corresponds to entityGroup-an array of EOEntity objects rooted to the same table. Inserts and deletes columns, and updates modified columns. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

statementsToUpdateObjectStoreForModel

public abstract NSArray statementsToUpdateObjectStoreForModel( EOModel model, NSDictionary changes, NSDictionary options)

Returns an array of EOSQLExpressions to synchronize the database with model. Prepares the statements to insert and delete new and deleted tables before invoking statementsToUpdateObjectStoreForEntityGroups for each modified table. The changes dictionary identifies the changes to make to the database schema; for more information, see "The Change Dictionary" (page 306). The options dictionary describes the aspects of the schema for which to create SQL statements; for more information, see "The Options Dictionary" (page 306).

supportsDirectColumnCoercion

public abstract boolean supportsDirectColumnCoercion()

Returns true if the adaptor can change the type of an existing column in place, false otherwise.

supportsDirectColumnDeletion

public abstract boolean supportsDirectColumnDeletion()

Returns true if the adaptor can delete columns, false otherwise.

supportsDirectColumnInsertion

public abstract boolean supportsDirectColumnInsertion()

Returns true if the adaptor can add columns to a table, false otherwise.

supportsDirectColumnNullRuleModification

public abstract boolean supportsDirectColumnNullRuleModification()

Returns true if the adaptor can modify the null rule of an existing column in place, false otherwise.

supportsDirectColumnRenaming

public abstract boolean supportsDirectColumnRenaming()

Returns true if the adaptor can rename table columns, false otherwise.

supportsSchemaSynchronization

public abstract boolean supportsSchemaSynchronization()

Returns true if the adaptor can update the database to reflect changes in a model, false otherwise.

Constant	Description
`SchemaSynchronizationPrimary KeySupportKey`	Key for use in options dictionaries. A corresponding value of "YES" indicates that the EOSQLExpression should generate SQL to create primary key support.
`SchemaSynchronizationPrimary KeyConstraintsKey`	Key for use in options dictionaries. A corresponding value of "YES" indicates that the EOSQLExpression should generate SQL to create primary key constraints.
`SchemaSynchronizationPrimary KeySupportKey`	Key for use in options dictionaries. A corresponding value of "YES" indicates that the EOSQLExpression should generate SQL to create foreign key constraints.
`AllowsNullKey`	Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.
`ColumnNameKey`	Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.
`ExternalNameKey`	Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.
`ExternalTypeKey`	Key for use in change dictionaries. A corresponding value indicates that the column's allows NULL value should be changed from.
`NameKey`	Key for use in change dictionaries. A corresponding value indicates the old value of the table or column.
`PrecisionKey`	Key for use in change dictionaries. A corresponding value indicates the value a column's precision should be changed from.
`RelationshipsKey`	Key for use in change dictionaries. The corresponding value is a dictionary of relationships which have been modified since the last time the model and schema were sychronized. For more information see "The Change Dictionary" (page 306).
`ScaleKey`	Key for use in change dictionaries. A corresponding value indicates the value the column's scale should be changed from.
`WidthKey`	Key for use in change dictionaries. A corresponding value indicates the value the column's width should be changed from.