Dynamic Views

For creating table using liquibase you can use below code and add it in your liquibase file. <createTable tableName=“employee”>      <column name="id" type="int">      <constraints primaryKey="true" nullable="false"/>   </column>      <column name="first_name" type="varchar(255)"/>   <column name="last_name" type="varchar(255)"/>   <column name="username" type="varchar(255)">      <constraints unique="true" nullable="false"/>   </column> </createTable> The use is pretty simple it's the way it looks : Tag: <createTable></createTable> This is an opening/ending tag for creating a table. These tags will enclose column sub tags which will define columns for the table. Attribute:   tableName : Name of the table which you want to create. (This is a mandatory   ...

Liquibase takes care of executing the query on the database while maintaining the list of queries executed and also maintaining the locks over the tables simultaneously. The two tables that are used by the liquibase for this purpose are : Databasechangeloglock : This table have following columns ID | LOCKED| LOCKGRANTED | LOCKEDBY. This maintains the locks information granted to the user. The primary purpose of this table is to make sure that two machines don't attempt to modify the data at the same time. Databasechangelog : This table have following columns ID | AUTHOR | FILENAME | DATEEXECUTED | ORDEREXECUTED | EXECTYPE | MD5SUM | DESCRIPTION | COMMENTS | TAG | LIQUIBASE This table maintains the list of the statements that are executed on the database.

liquibase.exception.LockException: Could not acquire change log lock. Currently locked by... Solution : Open your database and find the table named 'Databasechangeloglock', check the content of the Locked column. If it is set to '1' in that case the above exception will be thrown. Try setting it to '0' and set content of the 'LOCKGRANT' and 'LOCKEDBY' to (null). You might find this interesting. http://apdynamicviews.blogspot.in/2012/08/how-databasechangeloglock-and.html