How to reference the default schema in liquibase preCondition sqlCheck - sql

Posting here in case it helps someone.
TLDR: ${database.defaultSchemaName} within sqlCheck to access default schema name
I wanted my database changeset to first check if a certain row is present in the database. If not present, it should execute the changeset.
Example:
myschema.customers:
uuid
name
age
0001
Bob
22
0002
Sally
25
What I want: liquibase to check if uuid = 0002 is present in the myschema.customers table. If so, run the changeset, otherwise skip over it.
Initially I tried this:
<changeSet id="00000000000007" author="jhipster">
<preConditions onFail="MARK_RAN">
<sqlCheck expectedResult="0">
select count(*) from customers WHERE uuid= '0002'
</sqlCheck>
</preConditions>
<insert tableName="customers">
<column name="uuid" value="0002"></column>
<column name="name" value="Sally"></column>
<column name="age" value="25"></column>
</insert>
</changeSet>
Bear in mind that I have set the following configuration for liquibase (4.6.1)
spring:
liquibase:
default-schema: myschema
But it seems precondition sqlcheck was checking public.customers and not myschema.customers. This would cause an error when uuid 0002 is already present in myschema.customers.
SOLUTION: use ${database.defaultSchemaName}
<preConditions onFail="MARK_RAN">
<sqlCheck expectedResult="0">
select count(*) from ${database.defaultSchemaName}.customers WHERE uuid= '0002'
</sqlCheck>
</preConditions>

Related

How to copy the the data from one Table to another Table Using Liquibase scripts

I want to know the solution for the below Test ( to copy the the data from one Table to another Table) using Liquibase a part of Corda.
Case: As part of I want to create a new table into an existing database which has already a table called TableA (which has id, name, value columns) which has some data init, I have created a TableB (which has same id, name, value columns) and I wanted to copy the data from TableA to TableB.
For that I had used the following liquibase script as suggested here in Liquibase and In-order to test I had connected to PostgreSQL DB and connected schema called "corda_schema" which has the tables.
<changeSet author="liquibase.corda" id="update-table">
<update schemaName="corda_schema" tableName="TableB">
<column name="id" valueComputed="(SELECT id from TableA)"/>
<column name="name" valueComputed="(SELECT name from TableA)"/>
<column name="value" valueComputed="(SELECT value from TableA)"/>
</update>
</changeSet>
I was getting the following error when I tried with the Liquibase update script
Error: liquibase.corda failed
Error: schema "CORDA_SCHEMA" not found in SQL statement
If I don't given the schema name in update like this
<update tableName="TableB">
<column name="value" valueComputed="(SELECT value from TableA)"/>
</update>
the Liquibase is searching in the Public schema for TableA and I get this error:
Error: liquibase.corda failed Error: schema "PUBLIC" not found in SQL statement`
And also I tried this Liquibase script changeSet by creating the table itself I tried to update data, this changeSet is running and table is created but data is not copied.
<changeSet author="liquibase.corda" id="update-table">
<createTable schemaName = "corda_schema" tableName="TableB">
<column name="id" valueComputed= "(SELECT id FROM TableA)"/>
</createTable>
</changeSet>
Please suggest anything I am missing or any other usages that will make my test success to get the data from one table to another table.
Thanks in advance.
I would suggest to just use custom sql:
<changeSet author="liquibase.corda" id="insert-table">
<sql>
insert into corda_schema.TableB
select id,name,value from corda_schema.TableA;
</sql>
</changeSet>

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Building upon the question How to build a WHERE-clause in a LiquiBase changeset, I would like to choose the default value of a column based on the value of a column from a different table.
For instance, I have two tables, order and order_history. Pls note that we maintain all our orders in both order in order_history as well. Once an order is completed, it is removed from order table.
order has a column 'status' but we missed it on order_history, you can call it a bad design.
How do I add 'status' to order_history now, and copy the value from the corresponding order
in order table for existing data at the time of upgrade? Is there a way to do this in liquibase?
If order and order_history are connected with the foreign key, then you can just do the following:
<changeSet id="foo" author="bar">
<preConditions onFail="MARK_RAN">
<and>
<columnExists tableName="order" columnName="status"/>
<columnExists tableName="order_history" columnName="status"/>
</and>
</preConditions>
<comment>Update order_history.status with values from order.status, where order.id = order_history.order_id</comment>
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</changeSet>
If these tables are not connected, then you may use defaultValueComputed when you're adding a new column:
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</addColumn>

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In the same table I have to migrate the values of a column to a new one;
I want to create a new column,
populate it with the values of the other column and
remove the old column already migrated,
this must only happen if the new column has not already been created.
<changeSet author="xxxx" id="00021">
<preConditions onFail="MARK_RAN">
<not>
<columnExists schemaName="schema" tableName="talbee" columnName="new_table"/>
</not>
</preConditions>
<addColumn schemaName="schema" tableName="new_table">
<column name="new_column" type="text"/>
</addColumn>
<sql>UPDATE table_name SET new_column = old_column</sql>
<dropColumn
catalogName="cat"
columnName="old_column"
schemaName="schema"
tableName="table_name">
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</dropColumn>
</changeSet>
Is the way I delete the old column correct?
Is it better just to rename the column?
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<changeSet author="xxxx" id="00021">
<preConditions onFail="MARK_RAN">
<tableExists tableName="table_name"/>
<columnExists tableName="table_name" columnName="old_column"/>
<not>
<columnExists tableName="table_name" columnName="new_column"/>
</not>
</preConditions>
<renameColumn tableName="table_name" oldColumnName="old_column" newColumnName="new_column"
columnDataType="text"/>
</changeSet>

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Postgresql has type INTERVAL for column. But I didn`t found simple way to create table with such column.
I have solution with two steps:
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2. Use changeSet with sqlFile. Sql file contain sql for add column.
Example changeSet:
<changeSet author="author" id="add-testmy-table-v1">
<preConditions onFail="MARK_RAN">
<not>
<tableExists tableName="testmy"/>
</not>
</preConditions>
<createTable tableName="testmy">
<column autoIncrement="true" name="id" type="BIGSERIAL">
<constraints primaryKey="true" primaryKeyName="PK_testmy"/>
</column>
<column name="created_at" type="TIMESTAMP(6) WITHOUT TIME ZONE"/>
<column name="employee_id" type="BIGINT"/>
</createTable>
</changeSet>
<changeSet author="liquibase-docs" id="sql-example">
<sqlFile dbms="postgresql" encoding="utf8" path="testmy.sql" relativeToChangelogFile="true"/>
</changeSet>
testmy.sql file contain:
ALTER TABLE testmy
ADD COLUMN began_at INTERVAL ,
ADD COLUMN ended_at INTERVAL ;
Could anyone show another variant to solve such problem?

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I have a column attribute
on update CURRENT_TIMESTAMP
How can I remove it in xml changeset ? Database is mysql.
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<sql dbms="mysql">ALTER TABLE xxx MODIFY COLUMN yyy ????</sql>
</changeSet>
<changeSet id="someId" author="someAuthor" context="someContext">
<dropColumn tableName="tableName" columnName="columnNameToRemove" />
</changeSet>