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Last modified by christoph_lechleitner@iteg_at on 2013-01-31 07.32:56
From version 1.1
edited by 5fbc055b7cc103006957e1ae
on 2012-06-14 12.59:26
Change comment: There is no comment for this version
To version 4.1
edited by christoph_lechleitner@iteg_at
on 2013-01-31 04.25:51
Change comment: Name of schema history table configurable now, and text refactoring

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1 -=== {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-Preliminary"/}}Preliminary ===
1 += {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-Preliminary"/}}Preliminary =
2 2  
3 -The SchemaManager and SchemaEngine give you an abstracted access to the database schema of your application, allowing you to add and delete tables, fields and relations with application updates. It uses a designated table to keep track of the current schema status, which it will check whenever it is run, and update the database if it is not at the correct version.
3 +The SchemaManager ({{code language="none"}}org.clazzes.jdbc2xml.schema.SchemaManager{{/code}}) and SchemaEngine provide means to maintain the database scheme of an application, allowing you to add and delete tables, columns, relations and data in the database along application updates.
4 4  
5 -SchemaManager ({{code language="none"}}org.clazzes.jdbc2xml.schema.SchemaManager{{/code}}) will create a table called SCHEMA_HISTORY if it can not find it the first time it is run. This table contains the following columns:
5 +==== {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-SchemaHistoryTable"/}}Schema History Table ====
6 6  
7 +A designated schema table, by default named SCHEMA_HISTORY, is used to keep track of the current scheme. It will be automatically at SchemaManager's first run. (% style="font-size: 10.0pt;line-height: 13.0pt;" %)SCHEMA_HISTORY contains the following columns:
8 +
7 7  {{code language="none"}}
8 8  VERSION:varchar(10), not null, primary key
9 9  DESCRIPTION:varchar(512), nullable
... ... @@ -11,15 +11,25 @@
11 11  SERIALNR:integer(5), not null
12 12  {{/code}}
13 13  
14 -It will also take a list of TableInfo ({{code language="none"}}org.clazzes.jdbc2xml.schema.TableInfo{{/code}}) Objects and create a database from them, if it finds an empty database when it starts.
16 +In (% style="font-size: 10.0pt;font-weight: normal;line-height: 13.0pt;" %)heterogenous environments as well as in heavily modularized software architectures a single database may be shared by multiple parties each requiring a couple of tables.
15 15  
16 -
18 +(% style="font-size: 10.0pt;font-weight: normal;line-height: 13.0pt;" %)To allow multiple modules (applications, libraries, other OSGi bundles) to use (% style="font-size: 10.0pt;line-height: 13.0pt;" %)JDBC2XML's SchemaManager concurrently within one database, as of JDBC 1.1.1 SchemaManager hold the name of the schema history table in an overwritable property, {{code language="none"}}versionHistoryTable{{/code}}. See (%%)[[JDBCTOXML-11>>url:https://jira.clazzes.org/browse/JDBCTOXML-11||shape="rect"]](% style="font-size: 10.0pt;line-height: 13.0pt;" %).
17 17  
18 -=== {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-UsingOSGiandBlueprint"/}}Using OSGi and Blueprint ===
20 += {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-ProjectConfiguration"/}}Project Configuration =
19 19  
20 -After adding a dependency to the {{code language="none"}}org.clazzes.jdbc2xml{{/code}} library with your favourite package management system, add the following to your blueprint {{code language="none"}}services.xml{{/code}} configuration:
22 +SchemaManager requires a DataSource ({{code language="none"}}javax.sql.DataSource{{/code}}) and a list of TableInfo ({{code language="none"}}org.clazzes.jdbc2xml.schema.TableInfo{{/code}}) Objects, from which database structures will be created if an "empty" database is detected. Furthermore, an implementation of ISchemaEngine ({{code language="none"}}org.clazzes.jdbc2xml.schema.ISchemaEngine{{/code}}) is required.
21 21  
22 -{{code language="none"}}
24 +Optionally, a base version (default value 0.1.00) and a base description String (default "initial database schema") may be specified.
25 +
26 +Database updates are passed as a Map<String, ISchemaUpdateSnippet> (org.clazzes.jdbc2xml.schema.ISchemaUpdateSnippet) - details see below.
27 +
28 +To perform the operations, call {{code language="none"}}SchemaManager.start(){{/code}}.
29 +
30 +=== {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-ConfigurationusingSpringorOSGi/Blueprint"/}}Configuration using Spring or OSGi/Blueprint ===
31 +
32 +If you are using OSGi with Blueprint or Spring to set up your project, you can configure a SchemaManager instance by adding the following to your blueprint {{code language="none"}}services.xml{{/code}} (or Spring configuration file):
33 +
34 +{{code language="html/xml"}}
23 23  <bp:reference id="dialectFactory" interface="org.clazzes.jdbc2xml.schema.IDialectFactory">
24 24  </bp:reference>
25 25   
... ... @@ -27,7 +27,7 @@
27 27  </bp:reference>
28 28   
29 29  <bp:bean id="sqlDialect" factory-ref="dialectFactory" factory-method="newDialect">
30 -<bp:argument ref="jdbcUrl"> <!-- JDBC URL -->
42 +<bp:argument ref="jdbcUrl"><!-- bean jdbcUrl specified above -->
31 31  </bp:argument>
32 32  </bp:bean>
33 33   
... ... @@ -36,18 +36,212 @@
36 36  </bp:property>
37 37  </bp:bean>
38 38   
39 -<bp:bean id="databaseSetup" class="org.clazzes.jdbc2xml.schema.SchemaManager"
40 -init-method="start">
51 +<bp:bean id="databaseSetup" class="org.clazzes.jdbc2xml.schema.SchemaManager" init-method="start">
41 41  <bp:property name="dataSource" ref="dataSource"></bp:property>
42 42  <bp:property name="schemaEngine" ref="schemaEngine"></bp:property>
54 + <!-- optional but recommended: special name for schema history table: -->
55 + <bp:property name="versionHistoryTable" value="MYLIB_SCHEMA_HISTORY"/>
56 + <!-- optional but recommended: explicit first version -->
43 43  <bp:property name="baseVersion" value="0.1.00" />
44 44  <bp:property name="baseTables">
45 -<bp:bean factory-ref="tableDefinitions" factory-method="getSetup" />
59 +<!-- List of TableDefinitions here (see below), typical: -->
60 + <!-- <bp:bean factory-ref="tableDefinitions" factory-method="getSetup" /> -->
46 46  </bp:property>
47 47  <bp:property name="upateSnippets">
48 48  <!-- Add Update-Snippets here -->
64 + <!-- Example for update from 0.1.00 to 0.1.01 -->
65 + <!-- <bp:entry key="0.1.00" value="foo.schema.SchemaUpdate_0_1_01"></bp:entry> -->
49 49  </bp:property>
50 50  </bp:bean>
51 51  {{/code}}
52 52  
53 -The SchemaManager takes a map of
70 +By default, JDBC2XML provides an implementation of IDialectFactory and ISchemaEngineFactory as an OSGi service or via ServiceRegistry for Spring.
71 +
72 += {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-Settingupaninitialdatabaseschema"/}}Setting up an initial database schema =
73 +
74 +To create an initial database schema, SchemaManager needs a list of TableInfo objects.
75 +
76 +The recommended strategy is to implement a table definition class providing this list through a getter.
77 +
78 +This is an example:
79 +
80 +{{code language="java"}}
81 +package org.clazzes.example.jdbc2xml;
82 +
83 +import java.sql.Types;
84 +import java.util.Arrays;
85 +import java.util.List;
86 +
87 +import org.clazzes.jdbc2xml.schema.ColumnInfo;
88 +import org.clazzes.jdbc2xml.schema.ForeignKeyInfo;
89 +import org.clazzes.jdbc2xml.schema.PrimaryKeyInfo;
90 +import org.clazzes.jdbc2xml.schema.TableInfo;
91 + 
92 +public class TableDefinitions {
93 +
94 + // It is adviseable to provide the Strings used as names for tables and columns as constants, so they can be reused outside this object to build sql-statements
95 + public static final String TB_EXAMPLE_TABLE_NAME = "ADDRESSBOOK";
96 + public static final String COL_EXAMPLE_ID = "ID";
97 + public static final String COL_EXAMPLE_NAME = "NAME";
98 + public static final String COL_EXAMPLE_ADDRESS_REF = "ADDRESS";
99 + public static final String COL_EXAMPLE_BIRTHDAY = "BIRTHDAY";
100 + 
101 + // ...
102 + 
103 + private List<TableInfo> setup;
104 +
105 + public TableDefinitions() {
106 +// Create a table
107 +TableInfo exampleTable = new TableInfo(TB_EXAMPLE_TABLE_NAME);
108 +exampleTable.setColumns(
109 + Arrays.asList(new ColumnInfo[] {
110 +new ColumnInfo(COL_EXAMPLE_ID, Types.BIGINT, 20, null, false, null,true),
111 +new ColumnInfo(COL_EXAMPLE_NAME, Types.VARCHAR, 256, null, false, null),
112 +new ColumnInfo(COL_EXAMPLE_ADDRESS_REF, Types.BIGINT, 20, null, true, null),
113 +new ColumnInfo(COL_EXAMPLE_BIRTHDAY, Types.DATE, 12, null, false, null)
114 +}));
115 + 
116 +// Example for creating a foreign key reference
117 +exampleTable.setForeignKeys(Arrays.asList(new ForeignKeyInfo[] {
118 +new ForeignKeyInfo("FK_EXAMPLE_ADDRESS", COL_EXAMPLE_ADDRESS_REF, TB_ADDRESS, COL_ADDRESS_ID)
119 +}));
120 + 
121 +// Example for creating a primary key
122 +exampleTable.setPrimaryKey(
123 +new PrimaryKeyInfo("PK_EXAMPLE", COL_EXAMPLE_ID)
124 +);
125 +
126 +// ...
127 + 
128 +this.setup = Arrays.asList(
129 +exampleTable,
130 +// ...
131 +);
132 +
133 + }
134 +  
135 + public List<TableInfo> getSetup() {
136 +return this.setup;
137 + }
138 +
139 +}
140 +{{/code}}
141 +
142 +You must inject {{code language="none"}}TableDefinitions.getSetup(){{/code}} into {{code language="none"}}SchemaManager.setBaseTables(){{/code}} before calling {{code language="none"}}SchemaManager.start(){{/code}}.
143 +
144 +Using Blueprint/Spring, you can do this by inserting the following snippet in the bean definition for SchemaManager:
145 +
146 +{{code language="html/xml"}}
147 +<!-- SchemaManager bean definition starts here ... -->
148 +<bp:property name="baseTables">
149 +<bp:bean factory-ref="tableDefinitions" factory-method="getSetup" />
150 +</bp:property>
151 +<!-- ... and continues here -->
152 +{{/code}}
153 +
154 += {{id name="HowTocreateandupdateDatabasesusingSchemaManagerandSchemaUpdateSnippets-UpdatingadatabaseschemawithISchemaUpdateSnippet"/}}Updating a database schema with ISchemaUpdateSnippet =
155 +
156 +To update the database or it's content with schema updates, you must create a new implementation of ISchemaUpdateSnippet ({{code language="none"}}org.clazzes.jdbc2xml.schema.ISchemaUpdateSnippet{{/code}}) for each consecutive update. SchemaManager takes a {{code language="none"}}Map<String, Class<? extends ISchemaUpdateSnippet>>{{/code}} which contains the update classes keyed by the originating (e.g. previous) version.
157 +
158 +An example for an implementation of a schema update snippet could look like this:
159 +
160 +{{code language="java"}}
161 +package org.clazzes.example.jdbc2xml.updates;
162 +
163 +import java.sql.SQLException;
164 +import java.sql.Types;
165 +import java.util.Arrays;
166 +import org.clazzes.jdbc2xml.schema.ColumnInfo;
167 +import org.clazzes.jdbc2xml.schema.ISchemaEngine;
168 +import org.clazzes.jdbc2xml.schema.ISchemaUpdateSnippet;
169 +import org.clazzes.jdbc2xml.schema.PrimaryKeyInfo;
170 +import org.clazzes.jdbc2xml.schema.TableInfo;
171 +
172 +public class SchemaUpdate0_1_01 implements ISchemaUpdateSnippet {
173 + 
174 +// This is only accessed through the getter
175 +private static final String TARGET_VERSION = "0.1.01";
176 + 
177 +// Here it is also adviseable to define constants for reuse in statements.
178 +public static final String COL_EXAMPLE_GENDER = "GENDER";
179 +
180 +
181 +@Override
182 +public String getTargetVersion() {
183 +return TARGET_VERSION;
184 +}
185 +
186 +@Override
187 +public String getUpdateComment() {
188 +return "Adding column "+COL_EXAMPLE_GENDER+" to table "+TableDefinitions.TB_EXAMPLE_TABLE_NAME+".";
189 +}
190 +
191 +@Override
192 +public void performUpdate(ISchemaEngine schemaEngine) throws SQLException {
193 +TableInfo ti = schemaEngine.fetchTableInfo(TableDefinitions.TB_EXAMPLE_TABLE_NAME, null);
194 + schemaEngine.addColumn(ti, new ColumnInfo(COL_EXAMPLE_GENDER, Types.VARCHAR, 1, null, true, null));
195 +}
196 +}
197 +
198 +
199 +{{/code}}
200 +
201 +The return values of {{code language="none"}}ISchemaUpdateSnippet.getTargetVersion(){{/code}} and {{code language="none"}}ISchemaUpdateSnippet.getUpdateComment(){{/code}} are written to the {{code language="none"}}SCHEMA_HISTORY{{/code}} table. The update itself is performed in {{code language="none"}}ISchemaUpdateSnippet.performUpdate(){{/code}}. In the above example, it adds a column called {{code language="none"}}GENDER{{/code}} to the example table created by the TableDefinitions class above.
202 +
203 +To add an entire table you would use the {{code language="none"}}ISchemaEngine.createTable(){{/code}} method, like this:
204 +
205 +{{code language="java"}}
206 +@Override
207 +public void performUpdate(ISchemaEngine schemaEngine) throws SQLException {
208 + TableInfo tiGroup = new TableInfo(TB_GROUP);
209 + tiGroup.setColumns(Arrays.asList(new ColumnInfo[] {
210 + new ColumnInfo(TableDefinitions.COL_ID, Types.VARCHAR, 36, null, false, null),
211 + new ColumnInfo(TableDefinitions.COL_NAME, Types.VARCHAR, 100, null, false, null),
212 + new ColumnInfo(TableDefinitions.COL_DESCRIPTION, Types.VARCHAR, 512, null, true, null)
213 + }));
214 + tiGroup.setPrimaryKey(new PrimaryKeyInfo(PK_GROUP, TableDefinitions.COL_ID));
215 + tiGroup.setIndices(Arrays.asList(new IndexInfo(IDX_GROUP_01, TableDefinitions.COL_NAME, true, null)));
216 +
217 +schemaEngine.createTable(tiGroup, true);
218 +}
219 +{{/code}}
220 +
221 +Executing a PreparedStatement also works, using ISchemaEngine.getConnection() to retrieve the database connection:
222 +
223 +{{code language="java"}}
224 +@Override
225 +public void performUpdate(ISchemaEngine schemaEngine) throws SQLException {
226 + String sql = "UPDATE "+TableDefinitions.TB_EXAMPLE_TABLE_NAME+" SET "+TableDefinitions.COL_EXAMPLE_NAME+"=?";
227 +
228 + PreparedStatement ps = schemaEngine.getConnection().prepareStatement(sql);
229 +
230 + ps.setNull(1, Types.VARCHAR);
231 +
232 + ps.execute();
233 +}
234 +{{/code}}
235 +
236 +To create the map of updates in Blueprint/Spring and inject them into SchemaManager, use the following xml-Snippet:
237 +
238 +{{code language="html/xml"}}
239 +<!-- SchemaManager bean definition starts here ... -->
240 +<bp:property name="upateSnippets">
241 +<bp:map>
242 +<bp:entry key="0.1.00" value="org.clazzes.example.jdbc2xml.updates.SchemaUpdate0_1_01"></bp:entry>
243 +<!-- more entries come here: "key" is the schema version to update, "value" the qualified classname of the schema update -->
244 +</bp:map>
245 +</bp:property>
246 +<!-- ... and continues here -->
247 +{{/code}}
248 +
249 +
250 +
251 +
252 +
253 +
254 +
255 +
256 +
257 +
258 +
259 +
Confluence.Code.ConfluencePageClass[0]
Id
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1 -656804
1 +656825
URL
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1 -https://clazzes.atlassian.net/wiki/spaces/JDBC2XML/pages/656804/How To create and update Databases using SchemaManager and SchemaUpdateSnippets
1 +https://clazzes.atlassian.net/wiki/spaces/JDBC2XML/pages/656825/How To create and update Databases using SchemaManager and SchemaUpdateSnippets