liquibase.sqlgenerator.ext.AddColumnGeneratorHanaDB Maven / Gradle / Ivy

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Liquibase support for SAP Hana DB
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package liquibase.sqlgenerator.ext;

import liquibase.database.Database;
import liquibase.database.ext.HanaDBDatabase;
import liquibase.datatype.DataTypeFactory;
import liquibase.metadata.ForeignKeyConstraintMetaData;
import liquibase.sql.Sql;
import liquibase.sql.UnparsedSql;
import liquibase.sqlgenerator.SqlGeneratorChain;
import liquibase.sqlgenerator.core.AddColumnGenerator;
import liquibase.statement.AutoIncrementConstraint;
import liquibase.statement.core.AddColumnStatement;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;


public class AddColumnGeneratorHanaDB extends AddColumnGenerator {

    @Override
    public int getPriority() {
        return PRIORITY_DATABASE;
    }

    @Override
    public boolean supports(AddColumnStatement statement, Database database) {
        return database instanceof HanaDBDatabase;
    }

    @Override
    public Sql[] generateSql(AddColumnStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {
        if (!supports(statement, database)) {
            return sqlGeneratorChain.generateSql(statement, database);
        }

        String catalogName = statement.getCatalogName();
        String schemaName = statement.getSchemaName();
        if (schemaName == null) {
            schemaName = database.getDefaultSchemaName();
        }
        String tableName = statement.getTableName();
        String columnName = statement.getColumnName();
        String columnType = statement.getColumnType();

        String alterTable = "ALTER TABLE " + database.escapeTableName(catalogName, schemaName, tableName) +
                " ADD (" + database.escapeColumnName(catalogName, schemaName, tableName, columnName) +
                " " + DataTypeFactory.getInstance().fromDescription(columnType + 
                (statement.isAutoIncrement() ? "{autoIncrement:true}" : ""), database).toDatabaseDataType(database);

        if (statement.isAutoIncrement() && database.supportsAutoIncrement()) {
            AutoIncrementConstraint autoIncrementConstraint = statement.getAutoIncrementConstraint();
            alterTable += " " + database.getAutoIncrementClause(autoIncrementConstraint.getStartWith(), autoIncrementConstraint.getIncrementBy());
        }

        if (!statement.isNullable()) {
            alterTable += " NOT NULL";
        }

        if (statement.isPrimaryKey()) {
            alterTable += " PRIMARY KEY";
        }

        // "ALTER TABLE ADD COLUMN ..." does not support unique constraints in Hana
//        if (statement.isUnique()) {
//            alterTable += " UNIQUE ";
//        }

        alterTable += getDefaultClause(statement, database);

        if ( database instanceof HanaDBDatabase ) {
            alterTable += ")";
        }

        List returnSql = new ArrayList();
        
        // drop both incoming and outgoing foreign key constraints before adding column
        Set constraints = SqlGeneratorHelperHanaDB.getAllForeignKeyConstraints(database, schemaName, tableName);
        SqlGeneratorHelperHanaDB.addDropForeignKeyConstraintsStatements(returnSql, database, constraints);
        
        returnSql.add(new UnparsedSql(alterTable, getAffectedColumn(statement)));
        
        // recreate foreign key constraints
        SqlGeneratorHelperHanaDB.addCreateForeignKeyConstraintsStatements(returnSql, database, constraints);

        addForeignKeyStatements(statement, database, returnSql);

        return returnSql.toArray(new Sql[returnSql.size()]);
    }


    private String getDefaultClause(AddColumnStatement statement, Database database) {
        String clause = "";
        Object defaultValue = statement.getDefaultValue();
        if (defaultValue != null) {
            clause += " DEFAULT " + DataTypeFactory.getInstance().fromObject(defaultValue, database).objectToSql(defaultValue, database);
        }
        return clause;
    }

}