Liquibase - insert rows with uuid

问题

I have two tables declared as follows:

<changeSet author="istvan" id="country-table-changelog">
    <createTable tableName="country">
        <column name="id" type="uuid">
            <constraints nullable="false" unique="true" />
        </column>
        <column name="name" type="varchar">
            <constraints nullable="false" unique="true" />
        </column>
    </createTable>
</changeSet>

<changeSet author="istvan" id="region-table-changelog">
    <createTable tableName="region">
        <column name="id" type="uuid" >
            <constraints nullable="false" unique="true" />
        </column>
        <column name="country_id" type="uuid">
            <constraints nullable="false" />
        </column>
        <column name="name" type="varchar">
            <constraints nullable="false" unique="true" />
        </column>
    </createTable>
</changeSet>

<changeSet author="istvan" id="region-country-foreign-key-constraint">
    <addForeignKeyConstraint 
        baseTableName="region"
        baseColumnNames="country_id"
        referencedTableName="country"
        referencedColumnNames="id"
        constraintName="fk_region_country"
        onDelete="CASCADE" 
        onUpdate="RESTRICT"/>
</changeSet>

I want to fill both tables from liquibase changelog file with some values like:

INSERT INTO country VALUES('aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa', 'HUNGARY');
INSERT INTO region VALUES('bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb', 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa', 'Baranya');

In the example I used aaaa's and bbbb's just because of simplicity. I want to generate those UUID's by the DBMS.

What is the best way to do it? Do I have to use SQL in my changelog files or is it possible with XML? I prefer DBMS independent solution like XML or JSON.

My second question is that how can I declare a column with UUID that creates the UUID on insert. Something like:

<column name="id" type="uuid" value="??? GENERATE UUID ???">
    <constraints nullable="false" unique="true" />
</column>

Thank you for your time!

回答1:

You can do this by using properties that are defined depending on the current DBMS.

<property name="uuid_type" value="uuid" dbms="postgresql"/>
<property name="uuid_type" value="uniqueidentifier" dbms="mssql"/>
<property name="uuid_type" value="RAW(16)" dbms="oracle"/>

<property name="uuid_function" value="uid.uuid_generate_v4()" dbms="postgresql"/>
<property name="uuid_function" value="NEWID()" dbms="mssql"/>
<property name="uuid_function" value="sys_guid()" dbms="oracle"/>

Then use those properties when defining the table:

<column name="id" type="${uuid_type}" defaultValueComputed="${uuid_function}">
    <constraints nullable="false" unique="true" />
</column>

Note that you need to use defaultValueComputed, not value

If the column is defined with a default value, just leave it out in your insert statements and the database will then generate the UUID when inserting.

回答2:

For MySQL, put your property just before changeSet tag:

    <property name="u_id" value="uuid()" dbms="mysql"/>

then

    <column name="ID" type="varchar(255)" valueComputed="${u_id}"/>

NOTE: here valueComputed is used, not defaultValueComputed.

回答3:

Some databases supports UUID columns: Generate UUID values by default for each row on column of UUID type in H2 Database Engine

I don't think that Liquibase has embedded UUID generator, have a look at defaultValueComputed/valueComputed property for column (http://www.liquibase.org/documentation/column.html) + DB function to generate UUID

回答4:

Like Rammgarot noted, since we are dealing with columns that need to have unique values, we should use valueComputed instead of defaultValueComputed.

来源：https://stackoverflow.com/questions/42361350/liquibase-insert-rows-with-uuid

标签

sql

liquibase