DropColumnGenerator.java example

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siu-master
package liquibase.sqlgenerator.core;

import liquibase.database.Database;
import liquibase.database.core.*;
import liquibase.exception.ValidationErrors;
import liquibase.sql.Sql;
import liquibase.sql.UnparsedSql;
import liquibase.sqlgenerator.SqlGenerator;
import liquibase.sqlgenerator.SqlGeneratorChain;
import liquibase.statement.core.DropColumnStatement;

public class DropColumnGenerator extends AbstractSqlGenerator<DropColumnStatement> {

    public ValidationErrors validate(DropColumnStatement dropColumnStatement, Database database, SqlGeneratorChain sqlGeneratorChain) {
        ValidationErrors validationErrors = new ValidationErrors();
        validationErrors.checkRequiredField("tableName", dropColumnStatement.getTableName());
        validationErrors.checkRequiredField("columnName", dropColumnStatement.getColumnName());
        return validationErrors;
    }

    public Sql[] generateSql(DropColumnStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {
        if (database instanceof DB2Database) {
            return new Sql[] { new UnparsedSql("ALTER TABLE " + database.escapeTableName(statement.getSchemaName(), statement.getTableName()) + " DROP COLUMN " + database.escapeColumnName(statement.getSchemaName(), statement.getTableName(), statement.getColumnName())) };
        } else if (database instanceof SybaseDatabase || database instanceof SybaseASADatabase || database instanceof FirebirdDatabase || database instanceof InformixDatabase) {
            return new Sql[] { new UnparsedSql("ALTER TABLE " + database.escapeTableName(statement.getSchemaName(), statement.getTableName()) + " DROP " + database.escapeColumnName(statement.getSchemaName(), statement.getTableName(), statement.getColumnName())) };
        }
        return new Sql[] { new UnparsedSql("ALTER TABLE " + database.escapeTableName(statement.getSchemaName(), statement.getTableName()) + " DROP COLUMN " + database.escapeColumnName(statement.getSchemaName(), statement.getTableName(), statement.getColumnName())) };
    }
}