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| <!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "http://forrest.apache.org/dtd/document-v20.dtd">
|
| <document>
|
| <header>
|
| <title>Database support in DdlUtils</title>
|
| </header>
|
| <body> |
| <p> |
| DdlUtils accesses databases via JDBC, esp. the metadata that JDBC provides, as well as by |
| accessing database specific tables and performin database specific SQL. The details of the |
| latter can be found in the support documentation for the individual databases. |
| </p>
|
| <p>
|
| The main source of information about JDBC is the <a href="ext:java/jdbc/spec">JDBC Specification</a>,
|
| currently for JDBC version 3. General information about the JDBC datatypes can also be found in
|
| <a href="ext:java/jdbc/guide/types">Chapter 9: Mapping SQL and Java Types</a> of the
|
| <a href="ext:java/jdbc/guide">JDBC Technology Guide: Getting Started</a>. Please also note
|
| that some JDBC types are only available in recent versions of the Java platform, e.g.
|
| the <code>BOOLEAN</code> type is only available since J2SE version 1.4. These will be
|
| usable with DdlUtils only if you're running the respective Java version or a newer one.
|
| </p>
|
| <p>
|
| Here is a short summary of the information about the JDBC data types:
|
| </p>
|
| <p> </p>
|
| <table>
|
| <tr>
|
| <th>JDBC data type</th>
|
| <th>Format, Range, Size</th>
|
| <th>Comments</th>
|
| </tr>
|
| <tr>
|
| <td>ARRAY</td>
|
| <td></td>
|
| <td>Represents an array</td>
|
| </tr>
|
| <tr>
|
| <td>BIGINT</td>
|
| <td>-9223372036854775808 to 9223372036854775807</td>
|
| <td>64 bit signed integer</td>
|
| </tr>
|
| <tr>
|
| <td>BINARY</td>
|
| <td>254 bytes</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>BIT</td>
|
| <td>0, 1</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>BLOB</td>
|
| <td></td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>BOOLEAN</td>
|
| <td>true, false</td>
|
| <td>Java 1.4 and above</td>
|
| </tr>
|
| <tr>
|
| <td>CHAR</td>
|
| <td>254 (8-bit characters)</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>CLOB</td>
|
| <td></td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>DATALINK</td>
|
| <td></td>
|
| <td>Java 1.4 and above. References a file outside of the database but that
|
| is managed by it. Maps to <code>java.net.URL</code></td>
|
| </tr>
|
| <tr>
|
| <td>DATE</td>
|
| <td>year, month, day</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>DECIMAL</td>
|
| <td>15 for precision (total number of digits) and for scale (number of
|
| digits after the decimal point)</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>DISTINCT</td>
|
| <td></td>
|
| <td>Represents a distinct value, totally implementation dependent</td>
|
| </tr>
|
| <tr>
|
| <td>DOUBLE</td>
|
| <td>15 bits of mantissa (fractional part)</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>FLOAT</td>
|
| <td>15 bits of mantissa (fractional part)</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>INTEGER</td>
|
| <td>-2147483648 to 2147483647</td>
|
| <td>32 bit signed integer</td>
|
| </tr>
|
| <tr>
|
| <td>JAVA_OBJECT</td>
|
| <td></td>
|
| <td>Represents an java object, usually a serialized one</td>
|
| </tr>
|
| <tr>
|
| <td>LONGVARBINARY</td>
|
| <td>1 GB</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>LONGVARCHAR</td>
|
| <td>1 GB (8-bit characters)</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>NULL</td>
|
| <td></td>
|
| <td>Is not specified in detail</td>
|
| </tr>
|
| <tr>
|
| <td>NUMERIC</td>
|
| <td>15 for precision (total number of digits) and for scale (number of digits
|
| after the decimal point)</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>OTHER</td>
|
| <td></td>
|
| <td>Entirely database-specific type</td>
|
| </tr>
|
| <tr>
|
| <td>REAL</td>
|
| <td>7 bits of mantissa (fractional part)</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>REF</td>
|
| <td></td>
|
| <td>Represents a reference to an instance of a SQL structured type. Maps to
|
| <code>java.sql.Ref</code>.</td>
|
| </tr>
|
| <tr>
|
| <td>SMALLINT</td>
|
| <td>-32768 to 32767</td>
|
| <td>16 bit signed integer</td>
|
| </tr>
|
| <tr>
|
| <td>STRUCT</td>
|
| <td></td>
|
| <td>Represents a structured type, usually created via CREATE TYPE. Maps to
|
| <code>java.sql.Struct</code>.</td>
|
| </tr>
|
| <tr>
|
| <td>TIME</td>
|
| <td>hours, minutes, seconds</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>TIMESTAMP</td>
|
| <td>year, month, day, hours, minutes, seconds, nanoseconds</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>TINYINT</td>
|
| <td>-128 to 127 (8 bit signed) or 0 to 254 (8 bit unsigned)</td>
|
| <td>8 bit signed or unsigned integer</td>
|
| </tr>
|
| <tr>
|
| <td>VARBINARY</td>
|
| <td>254 bytes</td>
|
| <td></td>
|
| </tr>
|
| <tr>
|
| <td>VARCHAR</td>
|
| <td>254 bytes (8-bit characters)</td>
|
| <td></td>
|
| </tr>
|
| </table>
|
| </body>
|
| </document>
|
