# java.sql.DatabaseMetaData
java.sql.DatabaseMetaData是数据库对象定义接口。
表1对java.sql.DatabaseMetaData的支持情况 
| 方法名                                                                                                 | 返回值类型     | 支持JDBC 4 |
|:---|:---|:---|
| getTables(String catalog, String schemaPattern, String tableNamePattern, String\[\] types)          | ResultSet | Yes      |
| getColumns(String catalog, String schemaPattern, String tableNamePattern, String columnNamePattern) | ResultSet | Yes      |
| getTableTypes()                                                                                     | ResultSet | Yes      |
| getUserName()                                                                                       | String    | Yes      |
| isReadOnly()                                                                                        | boolean   | Yes      |
| nullsAreSortedHigh()                                                                                | boolean   | Yes      |
| nullsAreSortedLow()                                                                                 | boolean   | Yes      |
| nullsAreSortedAtStart()                                                                             | boolean   | Yes      |
| nullsAreSortedAtEnd()                                                                               | boolean   | Yes      |
| getDatabaseProductName()                                                                            | String    | Yes      |
| getDatabaseProductVersion()                                                                         | String    | Yes      |
| getDriverName()                                                                                     | String    | Yes      |
| getDriverVersion()                                                                                  | String    | Yes      |
| getDriverMajorVersion()                                                                             | int       | Yes      |
| getDriverMinorVersion()                                                                             | int       | Yes      |
| usesLocalFiles()                                                                                    | boolean   | Yes      |
| usesLocalFilePerTable()                                                                             | boolean   | Yes      |
| supportsMixedCaseIdentifiers()                                                                      | boolean   | Yes      |
| storesUpperCaseIdentifiers()                                                                        | boolean   | Yes      |
| storesLowerCaseIdentifiers()                                                                        | boolean   | Yes      |
| supportsMixedCaseQuotedIdentifiers()                                                                | boolean   | Yes      |
| storesUpperCaseQuotedIdentifiers()                                                                  | boolean   | Yes      |
| storesLowerCaseQuotedIdentifiers()                                                                  | boolean   | Yes      |
| storesMixedCaseQuotedIdentifiers()                                                                  | boolean   | Yes      |
| supportsAlterTableWithAddColumn()                                                                   | boolean   | Yes      |
| supportsAlterTableWithDropColumn()                                                                  | boolean   | Yes      |
| supportsColumnAliasing()                                                                            | boolean   | Yes      |
| nullPlusNonNullIsNull()                                                                             | boolean   | Yes      |
| supportsConvert()                                                                                   | boolean   | Yes      |
| supportsConvert(int fromType, int toType)                                                           | boolean   | Yes      |
| supportsTableCorrelationNames()                                                                     | boolean   | Yes      |
| supportsDifferentTableCorrelationNames()                                                            | boolean   | Yes      |
| supportsExpressionsInOrderBy()                                                                      | boolean   | Yes      |
| supportsOrderByUnrelated()                                                                          | boolean   | Yes      |
| supportsGroupBy()                                                                                   | boolean   | Yes      |
| supportsGroupByUnrelated()                                                                          | boolean   | Yes      |
| supportsGroupByBeyondSelect()                                                                       | boolean   | Yes      |
| supportsLikeEscapeClause()                                                                          | boolean   | Yes      |
| supportsMultipleResultSets()                                                                        | boolean   | Yes      |
| supportsMultipleTransactions()                                                                      | boolean   | Yes      |
| supportsNonNullableColumns()                                                                        | boolean   | Yes      |
| supportsMinimumSQLGrammar()                                                                         | boolean   | Yes      |
| supportsCoreSQLGrammar()                                                                            | boolean   | Yes      |
| supportsExtendedSQLGrammar()                                                                        | boolean   | Yes      |
| supportsANSI92EntryLevelSQL()                                                                       | boolean   | Yes      |
| supportsANSI92IntermediateSQL()                                                                     | boolean   | Yes      |
| supportsANSI92FullSQL()                                                                             | boolean   | Yes      |
| supportsIntegrityEnhancementFacility()                                                              | boolean   | Yes      |
| supportsOuterJoins()                                                                                | boolean   | Yes      |
| supportsFullOuterJoins()                                                                            | boolean   | Yes      |
| supportsLimitedOuterJoins()                                                                         | boolean   | Yes      |
| isCatalogAtStart()                                                                                  | boolean   | Yes      |
| supportsSchemasInDataManipulation()                                                                 | boolean   | Yes      |
| supportsSavepoints()                                                                                | boolean   | Yes      |
| supportsResultSetHoldability(int holdability)                                                       | boolean   | Yes      |
| getResultSetHoldability()                                                                           | int       | Yes      |
| getDatabaseMajorVersion()                                                                           | int       | Yes      |
| getDatabaseMinorVersion()                                                                           | int       | Yes      |
| getJDBCMajorVersion()                                                                               | int       | Yes      |
| getJDBCMinorVersion()                                                                               | int       | Yes      |