/** meta is a factory used to define forward mapping for tables and columns.
 * Functions are called to create Meta objects that are stored with field mappings.
 * The Meta objects returned from these functions can be annotated with additional properties.
 *
 * Functions that can be used with fields:
 *    meta.binary(lengthInBytes)       doit callback.binary(lengthInBytes, lob, nullable);
 *    meta.char(lengthInCharacters)    doit callback.char(lengthInCharacters, lob, nullable);
 *    meta.date()                      doit callback.date(nullable);
 *    meta.datetime(fsp)               doit callback.datetime(fsp, nullable);
 *    meta.decimal(precision, scale)   doit callback.decimal(precision, scale, nullable);
 *    meta.double()                    doit callback.double(nullable);
 *    meta.float()                     doit callback.float(nullable);
 *    meta.integer(bits)               doit callback.integer(bits, unsigned, nullable);
 *    meta.interval(fsp)               doit callback.interval(fsp, nullable);
 *    meta.int synonym for integer     doit callback.integer(bits, unsigned, nullable);
 *    meta.number synonym for decimal  doit callback.decimal(precision, scale, nullable);
 *    meta.time(fsp)                   doit callback.time(fsp, nullable);
 *    meta.timestamp(fsp)              doit callback.timestamp(fsp, nullable);
 *    meta.varchar(lengthInCharacters) doit callback.varchar(lengthInCharacters, lob, nullable);
 *    meta.varbinary(lengthInBytes)    doit callback.varbinary(lengthInBytes, lob, nullable);
 *    meta.year()                      doit callback.year(nullable);
 *
 * Meta objects can be modified to include additional properties that apply to field mapping:
 *    Meta.charset(name1, name2)       character set and collation; applies to char and varchar types
 *    Meta.hash()                      hash (only) index; applies to all indexable types
 *    Meta.lob()                       large object; applies to varbinary and varchar
 *    Meta.notNull()                   not null; applies to all types
 *    Meta.primaryKey()                primary key; applies to all primary key types
 *    Meta.uniqueKey()                 unique key; applies to all indexable types
 *    Meta.unsigned()                  unsigned; applies to integer types
 *
 * Examples: 
 *   tableMapping.mapField('id', meta.int(32).primaryKey().unsigned()) => id INT UNSIGNED PRIMARY KEY
 *   tableMapping.mapField('name', meta.varchar(32).notNull()) => name VARCHAR(32) NOT NULL
 *   tableMapping.mapField('ssn', meta.char(9).hash()) ==> ssn char(9) INDEX USING HASH
 *   tableMapping.mapField('scan', meta.varchar(1024000).lob() ==> TEXT(1024000)
 *
 * Functions that can be used with tables:
 *    meta.index([columnNames], optionalIndexName);
 *    meta.primaryKey([columnNames]);
 *    meta.uniqueKey([columnNames], optionalIndexName);
 *    meta.hashKey([columnNames], optionalIndexName);
 *    meta.orderedIndex([columnNames], optionalIndexName);
 *
 * Examples:
 *  new TableMapping('a', meta.primaryKey(['b', 'c'])); specifies primary key over columns b and c
 *  new TableMapping('a', meta.primaryKey(['b', 'c'])).hash; specifies hash-only primary key over columns b and c
 *  new TableMapping('a', meta.uniqueKey('b')); specifies unique ordered key over column b
 *  new TableMapping('a', meta.uniqueKey('b').hash()); specifies unique hash key over column b
 *  new TableMapping('a', meta.index('b')); specifies ordered index over column b
 *  new TableMapping('a', meta.hashKey('b')); specifies unique hash key over column b
 
 */
meta

/** Create a new Meta object that holds meta information. This constructor function is private,
 * and can only be used by a method on meta. All Meta objects are defined with a doit function
 * which calls back a function specific to the type of the Meta. The callback may be used
 * to create table definitions.
 */
Meta();

/** Call back the caller based on the type of Meta. See above for method called based on type.
 * A Meta constructed via meta.year() will call callback.year with the nullable value as a parameter
 * and return the value to the caller of doit.
 */
doit(callback);

/** Annotate a Meta with NOT NULL property. 
 @return this; // allows fluent method chaining
 */
notNull();

/** Annotate a Meta with UNSIGNED property. 
 @return this; // allows fluent method chaining
 */
unsigned();

/** Annotate a Meta with PRIMARY KEY property.
 @return this; // allows fluent method chaining
 */
primary();

/** Annotate a Meta with UNIQUE KEY property.
 * This annotation specifies an ordered index unless hash is also used.
 @return this; // allows fluent method chaining
 */
uniqueKey();
unique();

/** Annotate a Meta with USING HASH property. 
 * When used with primaryKey or uniqueKey, this specifies that the index created uses a hash index (only).
 @return this;
 */
hash();