Question

I seemed to be getting an exception when trying to upgrade/migrate DB’s. I seems to work until it get to a certain row i.e. 48586. I retested as though data was corrupted but same thing happen again. What the mysql is trying to do is drop the current primary key for table Logs, then add new primary keys IP, logId, logTime.

SEVERE 10/15/12 2:27 PM:liquibase: Error executing SQL ALTER TABLE `Logs` ADD PRIMARY KEY (`IP`, `logId`, `logTime`)
java.sql.SQLException: Data truncated for column 'logTime' at row 48586
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3597)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3529)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1990)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2151)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2619)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2569)
        at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:824)
        at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:667)
        at liquibase.executor.jvm.JdbcExecutor$1ExecuteStatementCallback.doInStatement(JdbcExecutor.java:92)
        at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:55)
        at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:105)
        at liquibase.database.AbstractDatabase.execute(AbstractDatabase.java:1014)
        at liquibase.database.AbstractDatabase.executeStatements(AbstractDatabase.java:998)
        at liquibase.changelog.ChangeSet.execute(ChangeSet.java:317)
        at liquibase.changelog.visitor.UpdateVisitor.visit(UpdateVisitor.java:27)
        at liquibase.changelog.ChangeLogIterator.run(ChangeLogIterator.java:58)
        at liquibase.Liquibase.update(Liquibase.java:113)
        at liquibase.integration.commandline.Main.doMigration(Main.java:684)
        at liquibase.integration.commandline.Main.main(Main.java:116)

Answer 1

As documented under MySQL Glossary:

primary key

A set of columns — and by implication, the index based on this set of columns — that can uniquely identify every row in a table. As such, it must be a unique index that does not contain any NULL values.

Under CREATE TABLE Syntax, then manual explains:

A PRIMARY KEY is a unique index where all key columns must be defined as NOT NULL. If they are not explicitly declared as NOT NULL, MySQL declares them so implicitly (and silently).

It would appear that your logTime column permitted (and contained) NULL values; attempting to create a PRIMARY KEY over it caused the column to be silently declared as NOT NULL, thereby “truncating” any NULL values to the column’s default value: the error is similar to ER_WARN_NULL_TO_NOTNULL.