package liquibase.change.core;
import liquibase.change.*;
import liquibase.database.Database;
import liquibase.snapshot.SnapshotGeneratorFactory;
import liquibase.statement.SqlStatement;
import liquibase.statement.core.SetNullableStatement;
import liquibase.structure.core.Column;
import liquibase.structure.core.Table;
/**
* Drops a not-null constraint from an existing column.
*/
@DatabaseChange(name="dropNotNullConstraint", description = "Makes a column nullable", priority = ChangeMetaData.PRIORITY_DEFAULT, appliesTo = "column")
public class DropNotNullConstraintChange extends AbstractChange {
private String catalogName;
private String schemaName;
private String tableName;
private String columnName;
private String columnDataType;
@DatabaseChangeProperty(mustEqualExisting ="notNullConstraint.table.catalog", since = "3.0")
public String getCatalogName() {
return catalogName;
}
public void setCatalogName(String catalogName) {
this.catalogName = catalogName;
}
@DatabaseChangeProperty(mustEqualExisting ="notNullConstraint.table.schema")
public String getSchemaName() {
return schemaName;
}
public void setSchemaName(String schemaName) {
this.schemaName = schemaName;
}
@DatabaseChangeProperty(mustEqualExisting = "notNullConstraint.table", description = "Name of the table containing that the column to drop the constraint from")
public String getTableName() {
return tableName;
}
public void setTableName(String tableName) {
this.tableName = tableName;
}
@DatabaseChangeProperty(mustEqualExisting = "notNullConstraint.column", description = "Name of the column to drop the constraint from")
public String getColumnName() {
return columnName;
}
public void setColumnName(String columnName) {
this.columnName = columnName;
}
@DatabaseChangeProperty(description = "Current data type of the column")
public String getColumnDataType() {
return columnDataType;
}
public void setColumnDataType(String columnDataType) {
this.columnDataType = columnDataType;
}
@Override
public SqlStatement[] generateStatements(Database database) {
//todo if (database instanceof SQLiteDatabase) {
// // return special statements for SQLite databases
// return generateStatementsForSQLiteDatabase(database);
// }
return new SqlStatement[] { new SetNullableStatement(
getCatalogName(),
getSchemaName(),
getTableName(), getColumnName(), getColumnDataType(), true)
};
}
@Override
public ChangeStatus checkStatus(Database database) {
try {
Column snapshot = SnapshotGeneratorFactory.getInstance().createSnapshot(new Column(Table.class, getCatalogName(), getSchemaName(), getTableName(), getColumnName()), database);
Boolean nullable = snapshot.isNullable();
return new ChangeStatus().assertComplete(nullable == null || nullable, "Column is not null");
} catch (Exception e) {
return new ChangeStatus().unknown(e);
}
}
// private SqlStatement[] generateStatementsForSQLiteDatabase(Database database) {
// // SQLite does not support this ALTER TABLE operation until now.
// // For more information see: http://www.sqlite.org/omitted.html.
// // This is a small work around...
//
// List<SqlStatement> statements = new ArrayList<SqlStatement>();
//
// // define alter table logic
// AlterTableVisitor rename_alter_visitor = new AlterTableVisitor() {
// public ColumnConfig[] getColumnsToAdd() {
// return new ColumnConfig[0];
// }
// public boolean copyThisColumn(ColumnConfig column) {
// return true;
// }
// public boolean createThisColumn(ColumnConfig column) {
// if (column.getName().equals(getColumnName())) {
// column.getConstraints().setNullable(true);
// }
// return true;
// }
// public boolean createThisIndex(Index index) {
// return true;
// }
// };
//
// try {
// // alter table
// statements.addAll(SQLiteDatabase.getAlterTableStatements(
// rename_alter_visitor,
// database,getCatalogName(), getSchemaName(),getTableName()));
// } catch (Exception e) {
// e.printStackTrace();
// }
// return statements.toArray(new SqlStatement[statements.size()]);
// }
@Override
protected Change[] createInverses() {
AddNotNullConstraintChange inverse = new AddNotNullConstraintChange();
inverse.setColumnName(getColumnName());
inverse.setSchemaName(getSchemaName());
inverse.setTableName(getTableName());
inverse.setColumnDataType(getColumnDataType());
return new Change[]{
inverse
};
}
@Override
public String getConfirmationMessage() {
return "Null constraint dropped from " + getTableName() + "." + getColumnName();
}
@Override
public String getSerializedObjectNamespace() {
return STANDARD_CHANGELOG_NAMESPACE;
}
}