`snapshot` command

The snapshot command captures the current state of the URL database, which is the target database.

The snapshot command has two modes:

When run without options, it gathers the current state of the database and shows a text-based version of the schema to STDOUT.
When run with the --snapshotFormat=JSON option, it creates a JSON file that represents the current state of the URL database. Alternatively, you can have a YAML-based output by using the --snapshotFormat=yaml attribute.

Uses

The snapshot command is typically used when you want to see changes in your target database or keep a record of your current database state.

The snapshot can be used in the diff command or diffChangeLog command.

Note: It is best practice to use the --snapshotFormat=JSON option for the diff and diffChangeLog commands. Otherwise, you will get only a text report of your target database. This text report cannot be used for comparison in the future.

It can also be used to compare:

A previous database state to an online database.
A previous database state to another snapshot.

Note: Running a diff command by using at least one snapshot.json file is faster than using a diff command with two online databases. However, keep in mind that a snapshot will no longer reflect the current state of the database if the database is changed with the update command or if it is changed manually.

Running the `snapshot` command

To run the snapshot command, you can specify your driver, classpath, and URL in your liquibase.properties file. For more information, see Creating and configuring a liquibase.properties file. You can also specify these properties in your command line.

Then run the snapshot command:

liquibase snapshot

Note: To create a JSON file, add the --snapshotFormat=json attribute while running the command:

liquibase --outputFile=mySnapshot.json snapshot --snapshotFormat=json

Note: Enter the name of the output file that you want to use in place of mySnapshot.json. Additionally, include --snapshotFormat=json to create a file in a JSON format.

`snapshot` global attributes

Attributes	Definition	Requirement
`--changeLogFile`	The root changelog	Required
`--username`	The database username	Required
`--password`	The database password	Required
`--url`	The JDBC database connection	Required
`--outputFile`*	Specifies the file path to where the snapshot JSON or YAML will be written	Optional

* If not specified, a JSON or YAML output goes to STDOUT.

Note: The username and password attributes are not required for connections and systems which use alternate means of authentication.

`snapshot` command attributes

Attributes	Definition	Requirement
`--snapshotFormat`	Creates a JSON or YAML file that represents the current state of the database.	Optional

Using the `snapshot` in the `diff` and `diffChangeLog` commands

You can use the JSON format snapshot file in the diff and diffChangeLog commands. One of the typical workflows is the following:

Make sure your local environment is up-to-date by getting the latest changelog from source control.
Configure your liquibase.properties file to point to a local development database and run the update command to ensure your target database matches the changelog file.
Take a snapshot of the local development database by running the snapshot command:

liquibase --outputFile=myschemaSnapshot.json snapshot --snapshotFormat=json

Manually change the local development database if needed.
Append changes to the changelog by running the diffChangeLog command:

liquibase --referenceUrl=jdbc:oracle:thin://localhost:9090/mem:test --url=offline:mysql?snapshot=mySnapshot.json diffChangeLog

Note: If you want to see changes without appending them to the changelog file, add --changeLogFile=mydiffchangelog.xml to the diffChangeLog command:

liquibase --referenceUrl=jdbc:oracle:thin://localhost:9090/mem:test --url=offline:mysql?snapshot=mySnapshot.json --changeLogFile=mydiffchangelog.xml diffChangeLog

Note: The format for the URL is the following: offline:<db_type>?snapshot=<path/to/snapshot.json>. Use the name of your database type from the list of the supported databases in place of <db_type> and the path relative to where the command is running in place of <path/to/snapshot.json>. If you are using another database, like H2, you may need to wrap your URL in ": "offline:<db_type>?snapshot=<path/to/snapshot.json>".

Review the changelog file to ensure that it matches your expectations of the manual changes that were made.
Mark the manual changes as deployed in the local development database by running the changelogSync command:

liquibase changeLogSync

Commit the changes to the source control.

Output

When running the snapshot command with the --snapshotFormat attribute, the output can be as follows:

Liquibase Pro 3.8.7 by Datical licensed to Liquibase Pro Customer until Tue Sep 22 19:00:00 CDT 2020
Liquibase command 'snapshot' was executed successfully.

When running the snapshot command without indicating the --snapshotFormat, you receive the following output:

Liquibase Pro 3.8.7 by Datical licensed to Liquibase Pro Customer until Tue Sep 22 19:00:00 CDT 2020
Database snapshot for jdbc:oracle:thin:@localhost:1521:ORCL
-----------------------------------------------------------------
Database type: Oracle
Database version: Oracle Database 11g Release 11.1.0.0.0 - Production
Database user: SCHEMA1
Included types:
com.datical.liquibase.ext.appdba.synonym.Synonym
com.datical.liquibase.ext.storedlogic.checkconstraint.CheckConstraint
com.datical.liquibase.ext.storedlogic.databasepackage.DatabasePackage
com.datical.liquibase.ext.storedlogic.databasepackage.DatabasePackageBody
com.datical.liquibase.ext.storedlogic.function.Function
com.datical.liquibase.ext.storedlogic.trigger.Trigger
liquibase.structure.core.Catalog
liquibase.structure.core.Column
liquibase.structure.core.ForeignKey
liquibase.structure.core.Index
liquibase.structure.core.PrimaryKey
liquibase.structure.core.Schema
liquibase.structure.core.Sequence
liquibase.structure.core.StoredProcedure
liquibase.structure.core.Table
liquibase.structure.core.UniqueConstraint
liquibase.structure.core.View

Catalog: SCHEMA1
	com.datical.liquibase.ext.storedlogic.function.Function:
		FUNCTION1
			body: CREATE OR REPLACE FUNCTION FUNCTION1 RETURN VARCHAR2 AS
			BEGIN
				RETURN NULL;
			END FUNCTION1;
			valid: true

	liquibase.structure.core.Index:
		PK_DATABASECHANGELOGLOCK
			columns:
				ID
			table: DATABASECHANGELOGLOCK
			unique: true
		PK_DEPARTMENT
			columns:
				ID
			table: DEPARTMENT
			unique: true
		PK_DEPARTMENT11
			columns:
				ID
			table: DEPARTMENT11
			unique: true
		PK_SERVICETECH22
			columns:
				ID
			table: LIBRARY2
			unique: true
		PK_SERVICETECH222
			columns:
				ID
			table: LIBRARY22
			unique: true
		PK_SERVICETECH
			columns:
				ID
			table: SERVICETECH
			unique: true

	liquibase.structure.core.PrimaryKey:
		PK_DATABASECHANGELOGLOCK
			backingIndex: PK_DATABASECHANGELOGLOCK
			columns:
				ID
			table: DATABASECHANGELOGLOCK
			validate: true
		PK_DEPARTMENT
			backingIndex: PK_DEPARTMENT
			columns:
				ID
			table: DEPARTMENT
			validate: true
		PK_DEPARTMENT11
			backingIndex: PK_DEPARTMENT11
			columns:
				ID
			table: DEPARTMENT11
			validate: true
		PK_SERVICETECH22
			backingIndex: PK_SERVICETECH22
			columns:
				ID
			table: LIBRARY2
			validate: true
		PK_SERVICETECH222
			backingIndex: PK_SERVICETECH222
			columns:
				ID
			table: LIBRARY22
			validate: true
		PK_SERVICETECH
			backingIndex: PK_SERVICETECH
			columns:
				ID
			table: SERVICETECH
			validate: true

	liquibase.structure.core.StoredProcedure:
		PROCEDURE1
			body: CREATE OR REPLACE PROCEDURE PROCEDURE1 AS
			BEGIN
				NULL;
			END PROCEDURE1;
			valid: true
						
	liquibase.structure.core.Table:
		DATABASECHANGELOG
			columns:
				AUTHOR
					nullable: false
					order: 2
					type: VARCHAR(255 BYTE)
				COMMENTS
					nullable: true
					order: 9
					type: VARCHAR(255 BYTE)
				CONTEXTS
					nullable: true
					order: 12
					type: VARCHAR(255 BYTE)
				DATEEXECUTED
					nullable: false
					order: 4
					type: TIMESTAMP(6)(11)
				DEPLOYMENT_ID
					nullable: true
					order: 14
					type: VARCHAR(10 BYTE)
				DESCRIPTION
					nullable: true
					order: 8
					type: VARCHAR(255 BYTE)
				EXECTYPE
					nullable: false
					order: 6
					type: VARCHAR(10 BYTE)
				FILENAME
					nullable: false
					order: 3
					type: VARCHAR(255 BYTE)
				ID
					nullable: false
					order: 1
					type: VARCHAR(255 BYTE)
				LABELS
					nullable: true
					order: 13
					type: VARCHAR(255 BYTE)
				LIQUIBASE
					nullable: true
					order: 11
					type: VARCHAR(20 BYTE)
				MD5SUM
					nullable: true
					order: 7
					type: VARCHAR(35 BYTE)
				ORDEREXECUTED
					nullable: false
					order: 5
					type: NUMBER(*, 0)
				TAG
					nullable: true
					order: 10
					type: VARCHAR(255 BYTE)
				DATABASECHANGELOGLOCK
					columns:
						ID
							nullable: false
							order: 1
							type: NUMBER(*, 0)
						LOCKED
							nullable: false
							order: 2
							type: NUMBER(1, 0)
						LOCKEDBY
							nullable: true
							order: 4
							type: VARCHAR(255 BYTE)
						LOCKGRANTED
							nullable: true
							order: 3
							type: TIMESTAMP(6)(11)
					indexes:
						PK_DATABASECHANGELOGLOCK
							columns:
								ID
							unique: true
						primaryKey: PK_DATABASECHANGELOGLOCK
							backingIndex: PK_DATABASECHANGELOGLOCK
							columns:
								ID
							validate: true
				DEPARTMENT
					columns:
						ACTIVE
							defaultValue: 1
							nullable: true
							order: 3
							type: NUMBER(1, 0)
						ID
							nullable: false
							order: 1
							type: NUMBER(*, 0)
						NAME
							nullable: false
							order: 2
							type: VARCHAR(50 BYTE)
					indexes:
						PK_DEPARTMENT
							columns:
								ID
							unique: true
					primaryKey: PK_DEPARTMENT
						backingIndex: PK_DEPARTMENT
							columns:
								ID
							validate: true
				DEPARTMENT11
					columns:
						ACTIVE
							defaultValue: 1
							nullable: true
							order: 3
							type: NUMBER(1, 0)
						ID
							nullable: false
							order: 1
							type: NUMBER(*, 0)
						NAME
							nullable: false
							order: 2
							type: VARCHAR(50 BYTE)
					indexes:
						PK_DEPARTMENT11
							columns:
								ID
							unique: true
					primaryKey: PK_DEPARTMENT11
						backingIndex: PK_DEPARTMENT11
						columns:
							ID
						validate: true
				LIBRARY2
					columns:
						ACTIVE
							defaultValue: 1
							nullable: true
							order: 3
							type: NUMBER(1, 0)
						ID
							nullable: false
							order: 1
							type: NUMBER(*, 0)
						NAME
							nullable: false
							order: 2
							type: VARCHAR(50 BYTE)
					indexes:
						PK_SERVICETECH22
							columns:
								ID
							unique: true
						primaryKey: PK_SERVICETECH22
							backingIndex: PK_SERVICETECH22
							columns:
								ID
							validate: true
				LIBRARY22
					columns:
						ACTIVE
							defaultValue: 1
							nullable: true
							order: 3
							type: NUMBER(1, 0)
						ID
							nullable: false
							order: 1
							type: NUMBER(*, 0)
						NAME
							nullable: false
							order: 2
							type: VARCHAR(50 BYTE)
					indexes:
						PK_SERVICETECH222
							columns:
								ID
							unique: true
					primaryKey: PK_SERVICETECH222
						backingIndex: PK_SERVICETECH222
						columns:
							ID
						validate: true
				SERVICETECH
					columns:
						ACTIVE
							defaultValue: 1
							nullable: true
							order: 3
							type: NUMBER(1, 0)
						ID
							nullable: false
							order: 1
							type: NUMBER(*, 0)
						NAME
							nullable: false
							order: 2
							type: VARCHAR(50 BYTE)
					indexes:
						PK_SERVICETECH
							columns:
								ID
							unique: true
					primaryKey: PK_SERVICETECH
						backingIndex: PK_SERVICETECH
						columns:
							ID
						validate: true

The snapshot command produces a JSON file that contains all your objects and places the file in the same directory as your changelog.

mySnapshot.json example


{
"snapshot": {
"created": "2019-10-23T16:10:40.306",
"database": {
"productVersion": "Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production\nWith the Partitioning option",
"shortName": "oracle",
"majorVersion": "11",
"minorVersion": "2",
"user": "MYSCHEMA",
"productName": "Oracle",
"url": "jdbc:oracle:thin:@localhost:1521:ORCL"
},
"objects": {
"com.datical.liquibase.ext.appdba.synonym.Synonym": [
{
"synonym": {
"name": "PRIVATETABLESYN",
"objectName": "PRIMARY_TABLE",
"objectSchema": "liquibase.structure.core.Schema#b689101",
"private": true,
"schema": "liquibase.structure.core.Schema#b689101",
"snapshotId": "b689152"
}
}
],
"liquibase.structure.core.Catalog": [
{
"catalog": {
"default": true,
"name": "MYSCHEMA",
"snapshotId": "b689100"
}
}
],
"liquibase.structure.core.Column": [
{
"column": {
"defaultValue": "1!{java.math.BigDecimal}",
"name": "ACTIVE",
"nullable": true,
"order": "3!{java.lang.Integer}",
"relation": "liquibase.structure.core.Table#b689129",
"snapshotId": "b689133",
"type": {
"columnSize": "1!{java.lang.Integer}",
"dataTypeId": "3!{java.lang.Integer}",
"decimalDigits": "0!{java.lang.Integer}",
"typeName": "NUMBER"
}
}
}
],
"liquibase.structure.core.Index": [
{
"index": {
"columns": [
"liquibase.structure.core.Column#b689137"
],
"name": "PK_DATABASECHANGELOGLOCK",
"snapshotId": "b689136",
"table": "liquibase.structure.core.Table#b689135",
"unique": true
}
}
],
"liquibase.structure.core.PrimaryKey": [
{
"primaryKey": {
"backingIndex": "liquibase.structure.core.Index#b689136",
"columns": [
"liquibase.structure.core.Column#b689137"
],
"name": "PK_DATABASECHANGELOGLOCK",
"snapshotId": "b689141",
"table": "liquibase.structure.core.Table#b689135",
"validate": true
}
}
],
"liquibase.structure.core.Schema": [
{
"schema": {
"catalog": "liquibase.structure.core.Catalog#b689100",
"default": true,
"name": "MYSCHEMA",
"snapshotId": "b689101"
}
}
],
"liquibase.structure.core.Table": [
{
"table": {
"columns": [
"liquibase.structure.core.Column#b689109",
"liquibase.structure.core.Column#b689110",
"liquibase.structure.core.Column#b689111",
"liquibase.structure.core.Column#b689112",
"liquibase.structure.core.Column#b689113",
"liquibase.structure.core.Column#b689114",
"liquibase.structure.core.Column#b689115",
"liquibase.structure.core.Column#b689116",
"liquibase.structure.core.Column#b689117",
"liquibase.structure.core.Column#b689118",
"liquibase.structure.core.Column#b689119",
"liquibase.structure.core.Column#b689120",
"liquibase.structure.core.Column#b689121",
"liquibase.structure.core.Column#b689122"
],
"name": "DATABASECHANGELOG",
"schema": "liquibase.structure.core.Schema#b689101",
"snapshotId": "b689108"
}
}
],
"liquibase.structure.core.View": [
{
"view": {
"columns": [
"liquibase.structure.core.Column#b689149",
"liquibase.structure.core.Column#b689150",
"liquibase.structure.core.Column#b689151"
],
"definition": "SELECT \"ID\",\"NAME\",\"ACTIVE\"\n  \nFROM \"MYSCHEMA\".\"DEPARTMENT\"",
"editioning": false,
"name": "VIEW1",
"schema": "liquibase.structure.core.Schema#b689101",
"snapshotId": "b689148"
}
}
],
"snapshotControl": {
"snapshotControl": {
"includedType": [
"com.datical.liquibase.ext.appdba.synonym.Synonym",
"com.datical.liquibase.ext.storedlogic.checkconstraint.CheckConstraint",
"com.datical.liquibase.ext.storedlogic.databasepackage.DatabasePackage",
"com.datical.liquibase.ext.storedlogic.databasepackage.DatabasePackageBody",
"com.datical.liquibase.ext.storedlogic.function.Function",
"com.datical.liquibase.ext.storedlogic.javalogic.JavaClass",
"com.datical.liquibase.ext.storedlogic.javalogic.JavaSource",
"com.datical.liquibase.ext.storedlogic.trigger.Trigger",
"liquibase.structure.core.Catalog",
"liquibase.structure.core.Column",
"liquibase.structure.core.ForeignKey",
"liquibase.structure.core.Index",
"liquibase.structure.core.PrimaryKey",
"liquibase.structure.core.Schema",
"liquibase.structure.core.Sequence",
"liquibase.structure.core.StoredProcedure",
"liquibase.structure.core.Table",
"liquibase.structure.core.UniqueConstraint",
"liquibase.structure.core.View"
]
}
}
}
}
}

Liquibase Community snapshot categories:

Catalog
Column
Foreign Key
Index
Primary Key
Schema
Sequence
Unique Constraints
View

Liquibase Pro snapshot categories:

Package
Package Body
Procedures
Function
Trigger
Synonyms
Check Constraints

snapshot command

Uses

Running the snapshot command

snapshot global attributes

snapshot command attributes

Using the snapshot in the diff and diffChangeLog commands

`snapshot` command

Running the `snapshot` command

`snapshot` global attributes

`snapshot` command attributes

Using the `snapshot` in the `diff` and `diffChangeLog` commands