8i | 9i | 10g | 11g | 12c | 13c | 18c | 19c | Misc | PL/SQL | SQL | RAC | WebLogic | Linux

Home » Articles » Misc » Here

SQLcl : Automating Your SQL and PL/SQL Deployments using the SQLcl implementation of Liquibase

This article gives a quick overview of applying changes to the database using the Liquibase implementation in SQLcl.

This is a rewrite of a Liquibase article, but using SQLcl instead of the regular Liquibase client.

Related articles.

That's Not How You Use It!

When you look at examples of using Liquibase on the internet they all have a few things in common.

The major issue for me is the way code objects are managed. This may not affect you if you never have code in the database, but for a PL/SQL developer, this feels like a show-stopper. As a result, I prefer to work using scripts, which are kept in source control, and use Liquibase as the deployment and sequencing mechanism. I'm sure many Liquibase users will not like this, and will think I'm using it incorrectly. That's fine.

I'm not hating on the Liquibase, or the SQLcl implementation of it. This is what feels right to me, but I reserve the right to change my mind!

Assumptions

You have SQLcl installed (see here).

For the examples here, we have a file system that look like one of these, depending on the OS used. Adjust as required.

Rem Windows
c:\git\my_project\changelogs                      : The location for the individual Liquibase changelogs.
c:\git\my_project\scripts                         : The location of any scripts referenced by Liquibase.
c:\git\my_project\changelogs\changelog_master.xml : The master.xml that maintains the changelog order.

# Linux
/git/my_project/changelogs                        : The location for the individual Liquibase changelogs.
/git/my_project/scripts                           : The location of any scripts referenced by Liquibase.
/git/my_project/changelogs/changelog_master.xml   : The master.xml that maintains the changelog order.

Notice I use the UNIX-style separator throughout the rest of the article. Liquibase and Windows don't really care about the separator. A path beginning with "/" is assumed to be relative to the current drive.

Supported Commands

The SQLcl HELP command displays the supported Liquibase commands. You can use either the full name "liquibase" or the "lb" shortcut.

SQL> help liquibase
        LB
        Provides a command line interface to Liquibase change management features from within SQLcl!
                Available commands are

                liquibase(lb) genobject <object_type> <object_name>
                liquibase(lb) genschema
                liquibase(lb) gencontrolfile
                liquibase(lb) update <CHANGE LOG> {include schema}
                liquibase(lb) updatesql <CHANGE LOG> {include schema}
                liquibase(lb) rollback <CHANGE LOG> <COUNT>
                liquibase(lb) diff <DEST URL> <DEST USER> <DEST PASS> {report}
                liquibase(lb) status <CHANGE LOG>
                liquibase(lb) validate <CHANGE LOG>
                liquibase(lb) changelogsync <CHANGE LOG>
                liquibase(lb) listlocks <CHANGE LOG>
                liquibase(lb) releaseLocks <CHANGE LOG>
                liquibase(lb) clearchecksums <CHANGE LOG>
                liquibase(lb) help <COMMAND>


SQL>

Generating a Changelog?

If you are starting to use Liquibase against an existing project, you can generate an initial changelog that represents your day 1 state. To demonstrate this, let's create some objects in a clean schema called "TEST".

CONN test/test@pdb1

CREATE TABLE tab1 (
  id          NUMBER,
  description VARCHAR2(50),
  CONSTRAINT tab1_pk PRIMARY KEY (id)
);

CREATE SEQUENCE tab1_seq;

INSERT INTO tab1 (id, description) VALUES (tab1_seq.NEXTVAL, 'Description for ' || tab1_seq.CURRVAL);
COMMIT;

CREATE OR REPLACE FUNCTION get_tab1_count RETURN NUMBER AS
  l_count  NUMBER;
BEGIN
  SELECT COUNT(*)
  INTO   l_count
  FROM   tab1;

  RETURN l_count;
END;
/

We generate an initial changelog to capture the state of our initial schema contents.

SQL> lb genschema
[Type - TYPE_SPEC]:                          379 ms
[Type - TYPE_BODY]:                          103 ms
[Type - SEQUENCE]:                            82 ms
[Type - CLUSTER]:                           2043 ms
[Type - TABLE]:                            11641 ms
[Type - MATERIALIZED_VIEW_LOG]:               49 ms
[Type - MATERIALIZED_VIEW]:                   27 ms
[Type - VIEW]:                              1436 ms
[Type - REF_CONSTRAINT]:                     126 ms
[Type - DIMENSION]:                           33 ms
[Type - FUNCTION]:                           131 ms
[Type - PROCEDURE]:                           76 ms
[Type - PACKAGE_SPEC]:                        62 ms
[Type - DB_LINK]:                             30 ms
[Type - SYNONYM]:                             51 ms
[Type - INDEX]:                             2293 ms
[Type - TRIGGER]:                            100 ms
[Type - PACKAGE_BODY]:                        96 ms
[Method loadCaptureTable]:                 18758 ms
[Method parseCaptureTableRecords]:           428 ms
[Method sortCaptureTable]:                    19 ms
[Method createExportChangeLogs]:               1 ms

Export Flags Used:
Export Grants           false
Export Synonyms         false
SQL>

This generates a number of files in the working directory, typically named after the object name with a siffix of the object type.

tab1_seq_sequence.xml       : The sequence definition.
tab1_table.xml              : The table definition.
get_tab1_count_function.xml : The function definition.
controller.xml              : The Liquibase master.xml.

The "controller.xml" file contains a reference to each changelog in the correct dependency order.

<?xml version="1.0" encoding="UTF-8"?> 
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">
  <include file="tab1_seq_sequence.xml"/> 
  <include file="tab1_table.xml"/> 
  <include file="get_tab1_count_function.xml"/> 
</databaseChangeLog>

The individual changelogs use the Liquibase XML format to describe the objects, with some Oracle extensions. The default object support is a lot better than the community Liquibase client, but it doesn't capture any data, so any seed data is not captured.

Even though this is more convincing than the regular Liquibase client, I still don't believe generating an initial changelog makes sense for all but the simplest projects. Instead, have a fixed point in time and start using Liquibase from there onward.

Create a master.xml (controller.xml)

The master.xml, also known as a controlfile or master index, is an ordered list of changelogs. SQLcl typically calls this "controller.xml", but the name is not important. When we start using Liquibase we can just create an empty one manually with the following contents.

<?xml version="1.0" encoding="UTF-8"?> 
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">

</databaseChangeLog>

SQLcl allows us to generate a new "controller.xml" file in the working directory.

SQL> lb gencontrolfile
Action successfully completed please review created file controller.xml
SQL>

The content looks similar to the previous empty file, but includes an example file inclusion tag.

<?xml version="1.0" encoding="UTF-8"?> 
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">
  <include file="{filename.xml}"/> 
</databaseChangeLog>

Every changelog that happens from now on has to be referenced in order from this master.xml.

We can create one that references every changelog in a specific directory, but this requires the changelogs to be named in a way that the application order is preserved, which could prove problematic. It feels safer to avoid this approach unless you are extremely disciplined.

<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">
    <includeAll path="/git/my_project/changelogs"/>
</databaseChangeLog>

Applying Changes

We have a script called "tab1_seq.sql" in our "/git/my_project/scripts" directory with the following contents.

-- tab1_seq.sql
CREATE SEQUENCE tab1_seq;

The comment line at the start of each SQL file is the file name. This isn't necessary, but it makes things a clearer when looking at the changelog.

We have a script called "tab1.sql" in our "/git/my_project/scripts" directory with the following contents.

-- tab1.sql
CREATE TABLE tab1 (
  id          NUMBER,
  description VARCHAR2(50),
  CONSTRAINT tab1_pk PRIMARY KEY (id)
);

INSERT INTO tab1 (id, description) VALUES (tab1_seq.NEXTVAL, 'Description for ' || tab1_seq.CURRVAL);
COMMIT;

We have a script called "get_tab1_count.sql" in our "/git/my_project/scripts" directory with the following contents.

-- get_tab1_count.sql
CREATE OR REPLACE FUNCTION get_tab1_count RETURNS NUMBER AS
  l_count  NUMBER;
BEGIN
  SELECT COUNT(*)
  INTO   l_count
  FROM   tab1;

  RETURN l_count;
END;
/

We want to apply these as a change to the database, so we create a changelog for them. Let's call this "changelog_00001_setup_tab1.xml" and place it in the "/git/my_project/changelogs" directory.

<?xml version="1.0" encoding="UTF-8"?> 
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">

    <changeSet author="tim" id="01_tab1_seq">
      <sqlFile dbms="oracle"
               endDelimiter=";"
               path="../scripts/tab1_seq.sql"
               relativeToChangelogFile="true"
               splitStatements="true"
               stripComments="false"/>
    </changeSet>
    <changeSet author="tim" id="02_tab1">
      <sqlFile dbms="oracle"
               endDelimiter=";"
               path="../scripts/tab1.sql"
               relativeToChangelogFile="true"
               splitStatements="true"
               stripComments="false"/>
    </changeSet>
    <changeSet author="tim" id="03_get_tab1_count">
      <sqlFile dbms="oracle"
               endDelimiter=";"
               path="../scripts/get_tab1_count.sql"
               relativeToChangelogFile="true"
               splitStatements="false"
               stripComments="false"/>
    </changeSet>
</databaseChangeLog>

There are some things to consider here.

We add a reference to this new changelog into the master.xml, so it now looks like this.

<?xml version="1.0" encoding="UTF-8"?> 
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">

  <include file="./changelog_00001_setup_tab1.xml" relativeToChangelogFile="true"/> 
</databaseChangeLog>

For SQLcl versions prior to 20.2, we can then apply the change using the following command.

SQL> CONN test/test@pdb1
Connected.
SQL> lb update /git/my_project/changelogs/changelog_master.xml
SQL>

From SQLcl version 20.2 onward we use a modified syntax.

SQL> CONN test/test@pdb1
Connected.
SQL> lb update -changelog /git/my_project/changelogs/changelog_master.xml
SQL>

This will create the objects associated with our change, and create some Liquibase objects to track the changes that have been applied.

COLUMN object_name FORMAT A30

SELECT object_name, object_type
FROM   user_objects
ORDER BY 1, 2;

OBJECT_NAME                    OBJECT_TYPE
------------------------------ -----------------------
DATABASECHANGELOG              TABLE
DATABASECHANGELOGLOCK          TABLE
GET_TAB1_COUNT                 FUNCTION
PK_DATABASECHANGELOGLOCK       INDEX
TAB1                           TABLE
TAB1_PK                        INDEX
TAB1_SEQ                       SEQUENCE

7 rows selected.

SQL>

If we describe the DATABASECHANGELOG table we can see the information that's captured.

SQL> DESC databasechangelog
Name          Null?    Type
------------- -------- -------------
ID            NOT NULL VARCHAR2(255)
AUTHOR        NOT NULL VARCHAR2(255)
FILENAME      NOT NULL VARCHAR2(255)
DATEEXECUTED  NOT NULL TIMESTAMP(6)
ORDEREXECUTED NOT NULL NUMBER(38)
EXECTYPE      NOT NULL VARCHAR2(10)
MD5SUM                 VARCHAR2(35)
DESCRIPTION            VARCHAR2(255)
COMMENTS               VARCHAR2(255)
TAG                    VARCHAR2(255)
LIQUIBASE              VARCHAR2(20)
CONTEXTS               VARCHAR2(255)
LABELS                 VARCHAR2(255)
DEPLOYMENT_ID          VARCHAR2(10)
SQL>

We display just the ID and FILENAME from the table. We can see the three changesets from our changelog.

COLUMN id FORMAT A17
COLUMN filename FORMAT A60

SELECT id, filename FROM databasechangelog;

ID                FILENAME
----------------- ------------------------------------------------------------
01_tab1_seq       /git/my_project/changelogs/changelog_00001_setup_tab1.xml
02_tab1           /git/my_project/changelogs/changelog_00001_setup_tab1.xml
03_get_tab1_count /git/my_project/changelogs/changelog_00001_setup_tab1.xml

SQL>

We then get a second set of changes.

We have a script called "tab2_seq.sql" in our "/git/my_project/scripts" directory with the following contents.

-- tab2_seq.sql
CREATE SEQUENCE tab2_seq;

We have a script called "tab2.sql" in our "/git/my_project/scripts" directory with the following contents.

-- tab2.sql
CREATE TABLE tab2 (
  id          NUMBER,
  description VARCHAR2(50),
  CONSTRAINT tab2_pk PRIMARY KEY (id)
);

We create a new changelog for this called "changelog_00002_setup_tab2.xml".

<?xml version="1.0" encoding="UTF-8"?> 
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">

    <changeSet author="tim" id="01_tab2_seq">
      <sqlFile dbms="oracle"
               endDelimiter=";"
               path="../scripts/tab2_seq.sql"
               relativeToChangelogFile="true"
               splitStatements="true"
               stripComments="false"/>
    </changeSet>
    <changeSet author="tim" id="02_tab2">
      <sqlFile dbms="oracle"
               endDelimiter=";"
               path="../scripts/tab2.sql"
               relativeToChangelogFile="true"
               splitStatements="true"
               stripComments="false"/>
    </changeSet>
</databaseChangeLog>

We add a reference to this new changelog into the master.xml, so it now looks like this.

<?xml version="1.0" encoding="UTF-8"?> 
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">

  <include file="./changelog_00001_setup_tab1.xml" relativeToChangelogFile="true"/> 
  <include file="./changelog_00002_setup_tab2.xml" relativeToChangelogFile="true"/> 
</databaseChangeLog>

We then apply the change the same way we did the first time. For SQLcl versions prior to 20.2 use this command.

SQL> CONN test/test@pdb1
Connected.
SQL> lb update /git/my_project/changelogs/changelog_master.xml
SQL>

From SQLcl version 20.2 onward use this command.

SQL> CONN test/test@pdb1
Connected.
SQL> lb update -changelog /git/my_project/changelogs/changelog_master.xml
SQL>

Liquibase knows it applied the first changelog already, so it applies only the second. We can see the new objects present in the database.

COLUMN object_name FORMAT A30

SELECT object_name, object_type
FROM   user_objects
ORDER BY 1, 2;

OBJECT_NAME                    OBJECT_TYPE
------------------------------ -----------------------
DATABASECHANGELOG              TABLE
DATABASECHANGELOGLOCK          TABLE
GET_TAB1_COUNT                 FUNCTION
PK_DATABASECHANGELOGLOCK       INDEX
TAB1                           TABLE
TAB1_PK                        INDEX
TAB1_SEQ                       SEQUENCE
TAB2                           TABLE
TAB2_PK                        INDEX
TAB2_SEQ                       SEQUENCE

10 rows selected.

SQL>

We query the DATABASECHANGELOG table, and we can see the two changesets from our second changelog have been applied.

COLUMN id FORMAT A17
COLUMN filename FORMAT A60

SELECT id, filename FROM databasechangelog;

ID                FILENAME
----------------- ------------------------------------------------------------
01_tab1_seq       /git/my_project/changelogs/changelog_00001_setup_tab1.xml
02_tab1           /git/my_project/changelogs/changelog_00001_setup_tab1.xml
03_get_tab1_count /git/my_project/changelogs/changelog_00001_setup_tab1.xml
01_tab2_seq       /git/my_project/changelogs/changelog_00002_setup_tab2.xml
02_tab2           /git/my_project/changelogs/changelog_00002_setup_tab2.xml

SQL>

Considerations

The Automatic Approach

I don't recommend this method for the reasons listed above, but I thought it was worth showing as it's interesting.

We start a new project and create the development and UAT users as follows.

CONN sys/SysPassword1@pdb1 AS SYSDBA
--ALTER SYSTEM SET DEFERRED_SEGMENT_CREATION=FALSE;

-- DROP USER dev CASCADE;
CREATE USER dev IDENTIFIED BY dev QUOTA UNLIMITED ON users;
GRANT CREATE SESSION, CREATE TABLE, CREATE SEQUENCE, CREATE PROCEDURE TO dev;

-- DROP USER uat CASCADE;
CREATE USER uat IDENTIFIED BY uat QUOTA UNLIMITED ON users;
GRANT CREATE SESSION, CREATE TABLE, CREATE SEQUENCE, CREATE PROCEDURE, CREATE VIEW, CREATE TRIGGER TO uat;

We make the first changes to the development schema.

CONN dev/dev@pdb1

CREATE SEQUENCE tab1_seq;

CREATE TABLE tab1 (
  id          NUMBER,
  description VARCHAR2(50),
  CONSTRAINT tab1_pk PRIMARY KEY (id)
);

CREATE OR REPLACE FUNCTION get_tab1_count RETURN NUMBER AS
  l_count  NUMBER;
BEGIN
  SELECT COUNT(*)
  INTO   l_count
  FROM   tab1;

  RETURN l_count;
END;
/

Switch directory to "v1" and use Liquibase to capture the first version of the schema contents.

mkdir -p /git/my_project/v1
cd /git/my_project/v1

sql dev/dev@pdb1 <<EOF
lb genschema
exit;
EOF

We are now ready to promote these changes to a UAT environment. We connect to the UAT environment and apply the changelogs.

cd /git/my_project/v1

sql uat/uat@pdb1 <<EOF
lb update controller.xml
exit;
EOF

We have a new change in development.

CONN dev/dev@pdb1

-- Change an existing tabe.
ALTER TABLE tab1 ADD (col3 DATE);

-- Create a new table.
CREATE SEQUENCE tab2_seq;

CREATE TABLE tab2 (
  id          NUMBER,
  description VARCHAR2(50),
  CONSTRAINT tab2_pk PRIMARY KEY (id)
);

-- Amend a code object (silly change).
CREATE OR REPLACE FUNCTION get_tab1_count RETURN NUMBER AS
  l_count  NUMBER;
BEGIN
  SELECT COUNT(*) + 1 - 1
  INTO   l_count
  FROM   tab1;

  RETURN l_count;
END;
/

Switch directory to "v2" and use Liquibase to capture the first version of the schema contents.

mkdir /git/my_project/v2
cd /git/my_project/v2

sql dev/dev@pdb1 <<EOF
lb genschema
exit;
EOF

We are now ready to promote these changes to a UAT environment. We connect to the UAT environment and apply the changelogs.

cd /git/my_project/v2

sql uat/uat@pdb1 <<EOF
lb update controller.xml false
exit;
EOF

For more information see:

Hope this helps. Regards Tim...

Back to the Top.