Package net.java.ao.db

Class MySQLDatabaseProvider

java.lang.Object
net.java.ao.DatabaseProvider
net.java.ao.db.MySQLDatabaseProvider
All Implemented Interfaces:
Disposable
public class MySQLDatabaseProvider extends DatabaseProvider
Author:
Daniel Spiewak

  • Field Details

  • Constructor Details

  • Method Details

    • renderAutoIncrement

      protected String renderAutoIncrement()
      Description copied from class: DatabaseProvider

      Generates the DDL fragment required to specify an INTEGER field as auto-incremented. For databases which do not support such flags (which is just about every database exception MySQL), "" is an acceptable return value. This method should never return null as it would cause the field rendering method to throw a NullPointerException.

      Overrides:
      renderAutoIncrement in class DatabaseProvider

    • renderAppend

      protected String renderAppend()
      Description copied from class: DatabaseProvider

      Generates any database-specific options which must be appended to the end of a table definition. The only database I am aware of which requires this is MySQL. For example:

      CREATE TABLE test (
     id INTEGER NOT NULL AUTO_INCREMENT,
     name VARCHAR(45),
     PRIMARY KEY(id)
 ) ENGINE=InnoDB;

      The "ENGINE=InnoDB" clause is what is returned by this method. The default implementation simply returns null, signifying that no append should be rendered.

      Overrides:
      renderAppend in class DatabaseProvider
      Returns:
      A DDL clause to be appended to the CREATE TABLE DDL, or null

    • renderUnique

      protected String renderUnique(UniqueNameConverter uniqueNameConverter, DDLTable table, DDLField field)
      Description copied from class: DatabaseProvider
      Renders the UNIQUE constraint as defined by the database-specific DDL syntax. This method is a delegate of other, more complex methods such as DatabaseProvider.renderField(net.java.ao.schema.NameConverters, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField, net.java.ao.DatabaseProvider.RenderFieldOptions). The default implementation just returns UNIQUE. Implementations may override this method to return an empty String if the database in question does not support the constraint.
      Overrides:
      renderUnique in class DatabaseProvider
      Returns:
      The database-specific rendering of UNIQUE.

    • renderQueryLimit

      protected String renderQueryLimit(Query query)
      Description copied from class: DatabaseProvider

      Renders the LIMIT portion of the query in the database-specific SQL dialect. There is wide variety in database implementations of this particular SQL clause. In fact, many database do not support it at all.

      Unfortunately, we live in the real world of proprietary database implementations that requires us to use database specific keywords or semantics to achieve these outcomes. Appropriate methods should be overridden in such cases.

      An example return value: " LIMIT 10,2"

      There is usually no need to call this method directly. Under normal operations it functions as a delegate for DatabaseProvider.renderQuery(Query, TableNameConverter, boolean).

      Overrides:
      renderQueryLimit in class DatabaseProvider
      Parameters:
      query - The Query instance from which to determine the LIMIT properties.
      Returns:
      The database-specific SQL rendering of the LIMIT portion of the query.

    • renderConstraintsForTable

      protected String renderConstraintsForTable(UniqueNameConverter uniqueNameConverter, DDLTable table)
      Description copied from class: DatabaseProvider
      Renders the foreign key constraints in database-specific DDL for the table in question. Actually, this method only loops through the foreign keys and renders indentation and line-breaks. The actual rendering is done in a second delegate method.
      Overrides:
      renderConstraintsForTable in class DatabaseProvider
      table - The database-agnostic DDL representation of the table in question.
      Returns:
      The String rendering of all of the foreign keys for the table.
      See Also:

    • renderAlterTableAddColumn

      protected Iterable<SQLAction> renderAlterTableAddColumn(NameConverters nameConverters, DDLTable table, DDLField field)
      Description copied from class: DatabaseProvider
      Generates the database-specific DDL statements required to add a column to an existing table. Included in the return value should be the statements required to add all necessary functions and triggers to ensure that the column acts appropriately. For example, if the field is tagged with an @OnUpdate annotation, chances are there will be a trigger and possibly a function along with the ALTER statement. These "extra" functions are properly ordered and will only be appended if their values are not null. Because of this, very few database providers will need to override this method.

      Each SQLAction should have a corresponding undo action; these will be executed in reverse order if the action needs to be rolled back.

      Overrides:
      renderAlterTableAddColumn in class DatabaseProvider
      table - The table which should receive the new column.
      field - The column to add to the specified table.
      Returns:
      An array of DDL statements to execute.
      See Also:
      • #renderFunctionForField(net.java.ao.schema.TriggerNameConverter, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField)
      • #renderTriggerForField(net.java.ao.schema.TriggerNameConverter, net.java.ao.schema.SequenceNameConverter, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField)

    • renderAlterTableChangeColumn

      protected Iterable<SQLAction> renderAlterTableChangeColumn(NameConverters nameConverters, DDLTable table, DDLField oldField, DDLField field)
      Description copied from class: DatabaseProvider

      Generates the database-specific DDL statements required to change the given column from its old specification to the given DDL value. This method will also generate the appropriate statements to remove old triggers and functions, as well as add new ones according to the requirements of the new field definition.

      The default implementation of this method functions in the manner specified by the MySQL database. Some databases will have to perform more complicated actions (such as dropping and re-adding the field) in order to satesfy the same use-case. Such databases should print a warning to stderr to ensure that the end-developer is aware of such restrictions.

      Thus, the specification for this method allows for data loss. Nevertheless, if the database supplies a mechanism to accomplish the task without data loss, it should be applied.

      For maximum flexibility, the default implementation of this method only deals with the dropping and addition of functions and triggers. The actual generation of the ALTER TABLE statement is done in the DatabaseProvider.renderAlterTableChangeColumnStatement(net.java.ao.schema.NameConverters, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField, net.java.ao.schema.ddl.DDLField, net.java.ao.DatabaseProvider.RenderFieldOptions) method.

      Overrides:
      renderAlterTableChangeColumn in class DatabaseProvider
      table - The table containing the column to change.
      oldField - The old column definition.
      field - The new column definition (defining the resultant DDL). @return An array of DDL statements to be executed.
      See Also:
      • #getTriggerNameForField(net.java.ao.schema.TriggerNameConverter, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField)
      • #getFunctionNameForField(net.java.ao.schema.TriggerNameConverter, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField)
      • #renderFunctionForField(net.java.ao.schema.TriggerNameConverter, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField)
      • #renderTriggerForField(net.java.ao.schema.TriggerNameConverter, net.java.ao.schema.SequenceNameConverter, net.java.ao.schema.ddl.DDLTable, net.java.ao.schema.ddl.DDLField)

    • renderCreateIndex

      protected SQLAction renderCreateIndex(IndexNameConverter indexNameConverter, DDLIndex index)
      Description copied from class: DatabaseProvider
      Generates the database-specific DDL statement required to create a new index. The syntax for this operation is highly standardized and thus it is unlikely this method will be overridden. If the database in question does not support indexes, a warning should be printed to stderr and null returned.
      Overrides:
      renderCreateIndex in class DatabaseProvider
      index - The index to create. This single instance contains all of the data necessary to create the index, thus no separate parameters (such as a DDLTable) are required.
      Returns:
      A DDL statement to be executed.

    • renderCreateCompositeIndex

      public SQLAction renderCreateCompositeIndex(String tableName, String indexName, List<String> fields)
      Description copied from class: DatabaseProvider
      Generates the database-specific DDL statement required to create a new composite index. This is only used by AO integration tests to create a composite index for testing. AO does not provide clients with a feature to manage composite indexes in any way.
      Overrides:
      renderCreateCompositeIndex in class DatabaseProvider
      Parameters:
      tableName - The name of the database table
      indexName - The name of the new index
      fields - List of fields that make up the index
      Returns:
      A DDL statement to be executed.

    • putNull

      public void putNull(PreparedStatement stmt, int index) throws SQLException
      Description copied from class: DatabaseProvider
      Stores an SQL NULL value in the database. This method is required due to the fact that not all JDBC drivers handle NULLs in the same fashion. The default implementation calls PreparedStatement.setNull(int, int), retrieving parameter type from metadata. Databases which require a different implementation (e.g. PostgreSQL) should override this method.
      Overrides:
      putNull in class DatabaseProvider
      Parameters:
      stmt - The statement in which to store the NULL value.
      index - The index of the parameter which should be assigned NULL.
      Throws:
      SQLException

    • getReservedWords

      protected Set<String> getReservedWords()
      Description copied from class: DatabaseProvider
      Retrieves the set of all reserved words for the underlying database. The set returns should be speculative, meaning that it should include any possible reserved words, not just those for a particular version. As an implementation guideline, the Set instance returned from this method should guarentee O(1) lookup times, otherwise ORM performance will suffer greatly.
      Specified by:
      getReservedWords in class DatabaseProvider
      Returns:
      A set of upper case reserved words specific to the database.

    • isCaseSensitive

      public boolean isCaseSensitive()
      Description copied from class: DatabaseProvider
      Flag indicating whether or not the underlying database uses case-sensitive identifiers. This specifically affects comparisons in the SchemaReader utility. The default value is true. Note that databases which support both case-sensetive and case-insensetive identifiers (like MySQL) should return true for better all-around compatibility.
      Overrides:
      isCaseSensitive in class DatabaseProvider
      Returns:
      boolean true if identifiers are case-sensetive, false otherwise.